Carrier Air Conditioner 37HS User Manual

37HS

Modulineா Air Terminals

Application Data

Page

CONTENTS

• VAV HEATING AND COOLING WITH

SYSTEM-POWERED CHANGEOVER

• VAV HEATING

Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

BUILDING LOAD CALCULATION . . . . . . . . . . 2-23

System-Powered Controls With

Electric Interface . . . . . . . . . . . . . . . . . . . . . . . . . 64

• VAV COOLING WITH ELECTRIC WARM-UP

• VAV HEATING AND COOLING WITH

ELECTRIC CHANGEOVER

• VAV COOLING WITH ELECTRIC HEAT

INTERLOCK

System-Powered Controls With

Pneumatic Interface . . . . . . . . . . . . . . . . . . . . . . 69

• PNEUMATIC SEQUENCED HEATING/

COOLING (HOT WATER)

• VAV COOLING WITH PNEUMATIC

WARM-UP OR FIRE SAFETY SWITCH

Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• LOAD CONSIDERATIONS

• DESIGN PROCEDURE

Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

• OVERHEAD AIR HEATING

TERMINAL SELECTION AND LAYOUT . . . . . 23-41

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Deﬁnitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Step 1 — Determine Air Volume (Cfm)

Per Terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Step 2 — Lay Out Terminals . . . . . . . . . . . . . . . 25

Step 3 — Consider Unit Combinations

and Run-Out Duct . . . . . . . . . . . . . . . . . . . . . . . . 27

Step 4 — Determine Controller Location . . . . 37

Final Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

AIRFLOW ADJUSTMENT . . . . . . . . . . . . . . . . . . 71,72

Maximum Airﬂow (Cfm) Adjustment . . . . . . . . 71

Minimum Airﬂow (Cfm) Adjustment . . . . . . . . . 71

Variation in Maximum Airﬂow . . . . . . . . . . . . . . 72

THE MODULINE VALVE . . . . . . . . . . . . . . . . . . . 41-44

The Moduline Control Concept . . . . . . . . . . . . . 41

• HIGH AND LOW PRESSURE

AIR DISTRIBUTION . . . . . . . . . . . . . . . . . . . . . . . . 73

Throw for Standard Diffusers . . . . . . . . . . . . . . . 82

• BELLOWS PRESSURE

• UNIT AIRFLOW DELIVERY

INTRODUCTION

CONTROL APPLICATIONS . . . . . . . . . . . . . . . . 44-50

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

System-Powered Controls . . . . . . . . . . . . . . . . . 44

• COMPONENTS OF THE SYSTEM-

POWERED CONTROL SYSTEM

The Moduline௡ air terminal (Fig. 1) is a truly ﬂexible unit

for the control and distribution of conditioned air to the oc-

cupied space. Available in 3 airﬂow sizes for single or mul-

tiple terminal installation, it is adaptable to a variety of

• SYSTEM-POWERED APPLICATIONS

Constant Volume (CV) Cooling

CV Heating

Variable Air Volume (VAV) Cooling

VAV Cooling With Warm-Up

VAV Heating and Cooling With Changeover

VAV Heating

• SYSTEM-POWERED CONTROLS WITH

ELECTRIC INTERFACE

VAV Cooling With Electric Warm-Up

VAV Heating and Cooling With Electric Changeover

VAV Cooling With Electric Heat Interlock

• SYSTEM-POWERED CONTROLS WITH

PNEUMATIC INTERFACE

Pneumatic Sequenced Cooling/Heating (Hot Water)

VAV Cooling With Pneumatic Warm-Up

VAV Cooling With Fire Safety

Night Set Back Heating

VAV Cooling/Separate System Heating

CONTROL SELECTION . . . . . . . . . . . . . . . . . . . 50-54

Control Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Control Packages . . . . . . . . . . . . . . . . . . . . . . . . . 50

CONTROL OPERATING SEQUENCES . . . . . . 55-71

System-Powered Controls . . . . . . . . . . . . . . . . . 55

• CV COOLING

• CV HEATING

• VAV COOLING

• VAV COOLING WITH WARM-UP

Fig. 1 — Moduline Air Terminal

Manufacturer reserves the right to discontinue, or change at any time, speciﬁcations or designs without notice and without incurring obligations.

Book 3

PC 201

Catalog No. 513-741

Printed in U.S.A.

Form 37HS-1XA

Pg 1

6-91

Replaces: New

Tab 6a

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Oversizing — Oversizing of variable volume systems re-

sults in unused equipment capacity and worse performance

at part load, not in increased system airﬂow. The actual sys-

tem operation will reﬂect the actual system load, not the de-

sign load. If conservative data, safety factors, or provision

for future loads are included in the design estimate, the ac-

tual system airﬂow will not be increased. The equipment will

be capable of handling an increased load should it ever ex-

ist, but will automatically throttle back to handle only the

actual load at that moment.

It is recommended that safety factors not be included in

load calculations; they are not included in the following method.

Air Motion, Ventilation and Odor Dilution — Air motion,

ventilation, and odor dilution deserve special attention in the

design of a VAV system. The designer must visualize the

correct system operating condition in order to evaluate the

adequacy of these items at either full or part-load cooling

conditions, or during the heating season.

Room air motion is determined by the supply air quantity

and the diffuser induction ratio. The minimum room air ve-

locity is higher if building humidity and temperature are higher.

The design cfm at peak cooling load in any zone should be

not less than the minimum shown below:

Fig. 3 — Estimating Block Load

DESIRED

ROOM TEMPERATURE

(F)

DESIGN CFM

AT PEAK COOLING

(cfm/sq ft)

0.7

0.4

These minimums are based on using the Carrier Modu-

line diffuser, which has very high performance; competitive

diffusers require a higher cfm/sq ft.

The outside air cfm requirement at maximum design con-

ditions may be determined by local building code. If the out-

side air cfm to the central air handler is adequate to maintain

a low overall building odor level, the odor level in a par-

ticular space will depend upon the odors generated locally in

that space and the supply airﬂow to that space. A space with

high odor generation (a conference room with much smok-

ing) should be provided with a separate exhaust system to

increase the air ﬂow through the space for odor dilution. The

only way to increase the VAV airﬂow to that space would be

to add reheat to increase the room sensible heat, which is

unacceptable from an energy conservation standpoint.

Fig. 4 — Floor Plan of Typical Zones

for Single-Story Office Building

LOAD CONSIDERATIONS

Lighting — Even though lighting loads (Watts/sq ft) are con-

siderably lower in today’s buildings, the lighting is by far

the largest load component.

It is necessary, therefore, to pay close attention to getting

an accurate estimate of the lighting requirements.

In estimating the lighting load, special consideration should

be given to evaluating storage effect and the performance of

return air ceiling plenums. Both of these items reduce the

peak room load from lights and delay the time at which the

stored heat becomes a load on the central equipment.

The following odor dilution cfm (either VAV supply or

supplemental exhaust cfm) is usually adequate:

Private or General Office — 0.25 cfm/sq ft

Major Conference Room — 1.0 cfm/sq ft

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1. Using the E20-II Block Load Program, select Cincinnati

for its weather data. The WEATHER PARAMETERS print-

out shown on pages 5 and 6 shows the weather data used

for the load estimating calculations.

Supply Air Temperature — In systems using draw-thru air

handling units and high induction Carrier Moduline௡ termi-

nal units, the acceptable range of supply air temperatures at

the terminals is from 50 to 54 F. The cooling coil ADP (Ap-

paratus Dew Point) will be from 3 to 5° F lower than the

supply air temperature, due to allowance for coil bypass, fan

heat and duct gain.

The system installed cost for ductwork, central air han-

dler, and VAV terminals will be greater if the air quantity is

higher because of the designer’s choice of a higher supply

air temperature. The increased fan air quantity will result in

higher fan operating cost, which may be offset by the lower

cost of operating the refrigeration system at a higher suction

temperature. The higher coil surface temperature (ADP) of

the system will result in a higher building humidity, which

will be less comfortable and require greater ventilation air.

2. The next step is to gather data on the building, including

dimensions, construction materials used, internal load pat-

terns (such as lighting levels) and the building orienta-

tion. For our example, we have divided the building into

nine zones. The actual building has ten zones on its north

exposure, but we’ve grouped them all into a single zone

because zones on the same exposure tend to have similar

load patterns. Similarly, the ten south exposure zones have

been grouped into a single zone, and the four east and

west zones have been combined into single east and west

zones respectively.

Pages 7-15 contain the ZONE DESCRIPTION printouts

for each of the nine zones.

An unduly low choice of supply air temperature may

result in unacceptably low room air motion in interior zones

with low lighting levels, and in unnecessarily low

humidity.

The same supply air temperature must be used for the zone

load and block load estimates.

3. The ﬁnal input step is to select an initial set of system

design data, including the cooling and heating set points,

the supply air temperature (or supply airﬂow rate, if that

is known) and the fan static pressure. This system design

data will, of course, be directly inﬂuenced by the actual

central station equipment, be it packaged or applied.

Load Calculating Methods — The cooling load estimates can

be made very accurately and quickly using the Carrier E20-II

Block Load program.

Because of the computer’s speed, it is not necessary to

compromise the design procedure to obtain the most accu-

rate result. The optimum design procedure listed here as-

sumes the use of the E20-II program, and may require ‘‘short

cuts’’ when using manual methods.

While the E-20 program is the most convenient and rapid

method of load calculation, other methods will also provide

the required results. In particular, Carrier multi-room load

estimating form E-5056 is available for this purpose.

Page 16 shows the HVAC SYSTEM DATA printout which

lists the system design data we’ve selected for this

example.

Load Calculations — With the input data from Step 1, the

Block Load Program calculates the building loads for each

month of the year to ﬁnd the largest load on the building’s

air conditioning system. Typically, this will occur during the

middle or late afternoon hours in July or August. The

SYSTEM SIZING SUMMARY printout shown on pages 17

and 18 provides both the cooling and heating equipment siz-

ing data. At the same time, it provides the maximum cooling

load, maximum heating load and design airﬂow rate for each

zone in the building. Notice that each zone may peak at a

month and hour different from that at which the HVAC sys-

tem peaks. The detailed system load report is shown on

page 19.

DESIGN PROCEDURE (with example)

Data Collection — Our example uses Cincinnati, Ohio as a

representative city. The building is a one-story office build-

ing with 11,250 sq ft. The building layout is shown in

Fig. 4 on page 3.

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Moduline௡ Selection (Analysis of Data) — The printout shown below presents an analysis of the preceding data.

Separate Duct Heating — A simple type of overhead air heat-

ing system for use with a Moduline cooling system consists

of a series of ceiling outlets, placed around the perimeter of

the building close to the outside wall, which blow warm air

outward and/or downward to ﬂoor level. The outlets are con-

nected by a simple duct system to an electric (or hot water)

heating-only fan coil unit located above the ceiling. (See

Fig. 5.) A minimum of one fan coil unit per exposure is used

for each story of the building. The fan coil unit draws air

from the ceiling plenum and distributes it to the building pe-

rimeter by means of a separate duct system. This type of

heating system operates at constant volume.

The separate duct heating approach allows heat to blanket

the outside wall, eliminating the transmission of heat through

the outside wall and permits the Moduline cooling units to

be located in the best arrangement for cooling distribution.

Control interlock between separate system heating and Modu-

line cooling is outlined in the Control Applications section,

on page 44.

Heating — Heat must be provided in a building to offset

losses through the perimeter walls, windows, and roof. In

the interior spaces the heat gain from lights and people will

in many cases be enough to cause a cooling load even in

winter.

The two most commonly used heating systems are these:

• Baseboard

• Overhead air

Baseboard has been used historically in the North because

it is effective in overcoming the downdraft from windows,

particularly with the large single pane windows used in the

past.

Now, with improvements in the building thermal enve-

lope due to better materials and construction methods, over-

head air heating is a viable and attractive alternative.

Overhead air heating, when properly applied, can handle

all requirements except the severe cases in which the wall U

values and temperature differences are large.

The 35BD heating slot boot diffuser (Fig. 6) is speciﬁ-

cally designed for this heating approach and will provide ex-

cellent distribution of the hot air necessary to offset the load.

Overhead air heating is the method which will be con-

sidered for these procedures.

OVERHEAD AIR HEATING — Two basic forms of over-

head heating are used with Moduline cooling systems:

• Separate duct heating

• Changeover Moduline heating/cooling

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Fig. 5 — Separate Duct Heating System

Performance Heating — Downblow Slot

NOMINAL

LENGTH (ft)

Placement

(in.)

Placement

(in.)

TYPE

DIFFUSER

Cfm

Min

Max

Min

Max

Heating Slot

Boot Diffuser

20-70

25-120

NOTES:

1. Minimum and maximum show distance diffuser should be lo-

cated from perimeter wall in inches.

2. For optimum performance of the diffuser, the air temperature should

be held between 90 and 115 F.

Fig. 6 — 35BD Heating Slot Boot Diffuser

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The Moduline location for heating and cooling requires

the unit to be a speciﬁc distance from the outside wall in

order to produce satisfactory distribution of the hot air. The

recommended location is shown in Fig. 8.

Changeover Moduline௡ Heating/Cooling — Both hot air and

cold air distribution are possible with a Moduline system.

The Moduline unit uses a director diffuser which, sensing

the duct temperature of the supply air, directs the air towards

or away from the perimeter wall. (Fig. 7.)

HEATING

COOLING

With cold air in the duct, the discharge is two-way blow — both into

the room and towards the wall.

With hot air in the duct, all discharge air is directed towards the

perimeter wall to offset the transmission.

Fig. 7 — Director Diffuser

DISTANCE TO OUTSIDE WALL ‘‘L’’

Minimum

Maximum

M − H

L =

Where:

2.5 Ft

M = Max Throw

for Heating

One-Way Blow

H = Ceiling Height

Fig. 8 — Recommended Location for Changeover Modulineா Heating/Cooling

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Additional Guidelines for Heating — In addition to down-

blow slot boot diffusers and Moduline director diffusers, round

nozzles spaced along the perimeter wall will also provide

satisfactory overhead heating distribution. Some guidance for

outlet use are shown in Tables 1 and 2.

TERMINAL SELECTION

AND LAYOUT

Introduction — Selecting the terminals and making a

layout is one of the most important steps in the design pro-

cess. This is where you use your knowledge to lay out the

job at a low cost and still give your client a satisfactory job.

There are 4 items which must be considered when select-

ing an air terminal:

Moduline heating and cooling is less ﬂexible than sepa-

rate duct system heating with Moduline cooling because:

• Moduline heating/cooling is a changeover system requir-

ing complete replacement of the cooling duct supply air

with heated air, making zone control difficult.

• air volume (Cfm) per terminal — a function of 1) the de-

sired sound level in the space, and 2) cost

• layout — a function of 1) the proper room air motion and

2) physical spacing

• unit combinations and run-out duct

• controller location

• Moduline location is a compromise between obtaining out-

side wall coverage with hot air and good cooling

distribution.

Thus, separate duct heating can provide heat for a given

exposure without materially affecting the building cooling

system. The heating outlets and Moduline terminals can be

located in the most efficient air distribution places of the con-

ditioned space.

Deﬁnitions — Following are deﬁnitions of terms used

when discussing the layout of a Moduline system.

Moduline units are arranged as single units or as units in

an air series.

SINGLE UNIT — A single unit is connected to the supply

duct and supplies conditioned air to a space or part of a space.

Fig. 9.

Table 1 — Optimum Outlet Discharge

AIR SERIES — Units in air series are connected unit-to-

unit or with interconnecting ductwork and the supply air for

all units enters the ﬁrst unit in the series. Fig. 10.

DIFFUSER SLOTS

VELOCITY (Fpm)

TEMPERATURE (F)

Downblow slots

Round nozzles

One-way blow slots

Director Diffusers

500 to 1250

900 to 1800

600 to 2200

800 to 2200

90 to 115

90 to 125

80 to 105

90 to 105

MASTER UNIT — A Moduline unit with controller, alone

or in air series, is a master unit. Fig. 11.

SLAVE UNIT — A unit in air series, controlled by another

unit (master unit) is a slave unit. Fig. 11.

CONTROLS — System-powered controls are installed at the

jobsite and consist of the components shown below:

Table 2 — Location Guidelines

MINIMUM

MAXIMUM

DISTANCE (ft)*

Constant Volume — Filter and volume controller.

DIFFUSER STYLE

DISTANCE (ft)*

Variable Volume, Diffuser Thermostat — Filter, volume con-

troller, thermostat with aspirator.

Variable Volume, Wall Thermostat — Filter, volume con-

troller, wall thermostat.

Round Nozzles and

Downblow Slots

1.0

2.0

One-Way Blow Slots

Director Diffusers

0.5

2.5

L†

*Feet away from outside wall.

†See Fig. 8.

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Fig. 9 — Single Modulineா Unit Connected to

Supply Duct

Fig. 12 — Control Block

Fig. 10 — Moduline Units in Air Series

Fig. 13 — Control End of Unit

Step 1 — Determine Air Volume (Cfm) Per Ter-

minal — Before you can start making a layout, you must

know the required air volumes (cfm).

Use the cfm per zone you obtained from the cooling load

calculation and, using Table 3, Recommended Maximum Cfm

Per Terminal, decide on the number of terminals you will

need in each zone.

Fig. 11 — Master Unit and Slave Units

Cost dictates that the fewest number of Moduline units be

used consistent with good design. The maximum cfm per

unit that can be used (to keep the total number of units down)

is mainly a function of maximum acceptable sound level.

Perimeter zones with glass in the east, west, and south

building zones have peaks of rather short duration (i.e. loads

vary widely during the course of the day and year). There-

fore, a higher sound level can be tolerated for these short

peaks.

CONTROL END — The control end of a Moduline௡ unit is

the end containing a control block at the end plate of the

valve section of the unit. (Fig. 12.) The end of the unit op-

posite the control end contains a blank block. The control

end of the Moduline unit is at the longer of the diffuser pro-

jections from the plenum. In Fig. 13, the longer projection,

B, is the control end.

The ﬁlter, volume controller, and diffuser-mounted ther-

mostat are applied to the control end of a master unit.

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As a result, slightly higher maximum cfm per unit is al-

lowed as compared to interior zones or the north perimeter,

which have relatively constant loads.

The maximum cfm per unit also is affected by the desired

sound level in the room and the type of use of the space.

Most jobs use a 2- x 4-ft grid T-Bar ceiling with 2- x 4-ft

or 2- x 2 ft tiles.

The ﬁrst consideration in making a layout is to place the

terminals as economically as possible in the grid, which means

locating the terminals perpendicular to the main tees.

For example, an executive office uses low sound levels

but the furnishings generally absorb more sound so the al-

lowable cfm/unit is only slightly lower than other types of

rooms.

Main tees (the ones with hangers) are 4 ft on center (nor-

mally) and the cross tees are spaced 2 ft apart between the

mains to make up a 2- x 4-ft T-bar grid. Additional trim tees

may be used to divide the ceiling into a 2- x 2-ft grid.

The Moduline units use mounting brackets and hang from

(run perpendicular to) the main tees. While the units can be

installed anywhere between mains, the most common loca-

tion is on the center line of the cross tee (replaces the cross

tee). The next most common location is half way between

cross tees. See Fig. 15.

While less desirable, the units can be run parallel to the

main tees. Unless absolutely necessary the units should not

replace the main tee because this means the main tee must

be cut. A location halfway between the mains is common

and in this case additional hangers are required to the upper

plenum of the unit or to the cross tee near the unit.

Table 3 — Recommended Maximum Cfm

Per Terminal

MODULINE UNITS

37HS1

37HS2

37HS4

TYPE OF

SPACE USE

East

West

and

East

West

and

East

West

and

Interior

and

North

Interior

and

North

Interior

and

North

South

General

Office

110

100

220

200

180

170

190

180

160

150

400

330

300

280

350

300

270

250

With

Carpet

Private

Office

With

Tile

Special units are available for many other types of

ceilings.

Executive

Office

Step 2 — Lay Out Terminals

LOCATE UNITS IN T-BAR GRID — In making a layout,

begin with a plan view of the ceiling. Normally, the ceiling

grid and the lighting is done ﬁrst and the diffuser plan must

ﬁt the layout.

The center of the room is the ideal location, but where

that space has been reserved for lighting, the Moduline dif-

fuser has enough ﬂexibility to provide good distribution when

not centered in the room.

For a two-way blow diffuser, anywhere from the ¹⁄4 point

to the ⁄4 point (wall to wall) is usually suitable. Outside of

the ¹⁄4 points, a one-way blow diffuser may be needed. Use

two-way blow diffuser wherever possible and one-way blow

only when really necessary. (See Fig. 14.)

Fig. 15 — Terminal Location

Fig. 14 — Diffuser Locations for

Preferred 2-Way or One-Way Blow

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EVALUATE THE THROW OF MODULINE௡ UNITS IN

POSSIBLE LOCATIONS — Check minimum throw for

2-way blow diffuser near walls and all one-way blow

diffusers.

Table 4 — Air Throw Data —

1-Way and 2-Way Blow, 2-Slot Diffusers

OPTIMUM AIR THROW (ft)

37HS1 UNIT

AIRFLOW

(Cfm)

1-Way Blow

2-Way Blow

Exceeding maximum throw is almost never a problem. A

2-way blow unit covers 50 ft at nominal cfm.

Min

Max

Min

Max

2.0

4.0

7.0

9.0

2.0

3.0

3.5

4.0

4.5

5.0

6.0

7.0

5.0

6.0

7.5

12.0

15.0

18.0

20.0

22.0

24.0

7.5

In perimeter rooms, if 2-way blow units are off center,

favor the exterior wall if possible.

8.0

9.0

10.0

11.0

12.0

9.0

10.5

11.5

13.0

15.0

Generally, one-way blow diffusers should blow away from

the nearest wall.

100

110

Air throw data in Tables 4 and 5 for the Moduline௡ air

terminals provides the suggested minimum and maximum

coverages the units can handle in a typical installation while

maintaining the desired room conditions.

OPTIMUM AIR THROW (ft)

1-Way Blow 2-Way Blow

37HS2 UNIT

AIRFLOW

(Cfm)

Min

Max

Min

Max

100

120

140

160

180

200

220

2.0

4.0

7.0

9.0

2.0

3.0

3.5

4.0

4.5

5.0

6.0

7.0

5.0

6.0

7.5

12.0

15.0

18.0

20.0

22.0

24.0

7.5

The optimum air throw values given in the table are dis-

tances from the unit centerline to the outside wall or nearest

obstruction (wall, light ﬁxture, or opposing air stream).

8.0

9.0

10.0

11.0

12.0

9.0

10.5

11.5

13.0

15.0

When given a choice, always put diffusers in line with each

other, not blowing at each other. If diffusers must be placed

so they are blowing at each other, the minimum throw must

be checked. Do not put units closer together than minimum

allows. Down-drafts caused by going below minimum will

bother room occupants. (Fig. 16)

OPTIMUM AIR THROW (ft)

1-Way Blow 2-Way Blow

37HS4 UNIT

AIRFLOW

(Cfm)

Min

Max

Min

Max

160

200

250

300

350

400

440

8.5

10.0

11.0

12.0

14.0

15.0

17.0

16.0

20.0

21.0

22.0

23.0

25.0

29.0

5.0

6.0

7.0

10.0

13.0

17.0

19.0

21.0

24.0

7.0

Moduline௡ units can be placed fairly close to a wall or

partition. This is because the down-draft follows the wall

(stays close to the wall) and doesn’t bother the room occu-

pant. If furniture is placed against the wall near a Moduline

unit, it causes the air to be deﬂected causing drafts. The prob-

lem can often be solved by moving the furniture 6 in. or so

away from the wall.

8.0

9.0

10.0

13.0

Table 5 — Air Throw Data —

2-Way and 1-Way Director, 3-Slot Diffusers

OPTIMUM AIR THROW (ft)

37HS1 UNIT

Heating

Cooling

AIRFLOW

(Cfm)

1-Way Blow

2-Way Blow

Min

Max

Min

Max

2.0

4.0

7.0

9.0

2.0

3.0

3.5

4.0

4.5

5.0

6.0

7.0

5.0

6.0

7.5

12.0

15.0

18.0

20.0

22.0

24.0

7.5

8.0

9.0

10.0

11.0

12.0

9.0

10.5

11.5

13.0

15.0

100

110

OPTIMUM AIR THROW (ft)

Heating Cooling

1-Way Blow 2-Way Blow

37HS2 UNIT

AIRFLOW

(Cfm)

Min

Max

Min

Max

100

120

140

160

180

200

220

2.0

4.0

7.0

9.0

2.0

3.0

3.5

4.0

4.5

5.0

6.0

7.0

5.0

6.0

7.5

12.0

15.0

18.0

20.0

22.0

24.0

7.5

8.0

9.0

10.0

11.0

12.0

9.0

10.5

11.5

13.0

15.0

OPTIMUM AIR THROW (ft)

Heating Cooling

1-Way Blow 2-Way Blow

37HS4 UNIT

AIRFLOW

(Cfm)

Fig. 16 — Locate Units to Prevent Down-Drafts

Min

Max

Min

Max

160

200

250

300

350

400

440

8.5

10.0

11.0

12.0

14.0

15.0

17.0

16.0

20.0

21.0

22.0

23.0

25.0

29.0

5.0

6.0

7.0

10.0

13.0

17.0

19.0

21.0

24.0

7.0

8.0

9.0

10.0

13.0

NOTES:

1. Minimum air throw refers to the distance from the diffuser where the air ve-

locity is 150 fpm. In maximum air throw, this velocity has dropped to 50 rpm.

2. Data is based on an area with a 9-ft ceiling. For higher ceilings, values may

be reduced by one foot for each foot of height increase. For speciﬁc instal-

lations, minimum values can be reduced if properly qualiﬁed. Values are

dependent on cfm only and are not affected by duct pressure.

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STAGGER SPACING — A frequently used layout method

is to stagger the units. This arrangement gives good cover-

age, solves the problem of drafts when units blow at each

other, and is low cost. It also gives good ﬂexibility for future

partition changes. (Fig. 17.)

Step 3 — Consider Unit Combinations And Run-

Out Duct — When the preliminary office layout is com-

plete, the trunk or main duct can be laid on the ﬂoor plan.

We are now ready for positioning the units in the space ac-

cording to the load calculations and the design of the run-out

ducts.

The zone load calculation provides the cfm requirements

for each space. Using those requirements and the ceiling lay-

out, the unit location and run-out can be determined. Figure

19 shows a single Moduline unit located on the grid line in

the approximate center of the space. Figure 20 shows mul-

tiple units in an air series located in similar fashion.

RECOMMENDED UNIT COMBINATIONS — Tables 6-8

list the recommended combinations of Moduline terminals.

Each model (size) of Moduline terminal is shown in com-

binations of 2, 3, 4 and 5 plenum sizes. To illustrate the use

of the tables, consider the 37HS2 for a space requiring 550

cfm. Three units in air series will provide the capacity. (Note

that 550 cfm is below the max cfm limit of 660 shown in

Table 7.) Six combinations of 37HS2 units are available; all

will produce a good installation. However, some factors in-

ﬂuence the choice:

If it is desirable to have common plenum sizes throughout

the space, the choice will be three 9 x 9-in. plenums.

Fig. 17 — Staggered Units

The lowest inlet velocities will result in the least variance

of discharge cfm among the 3 units on one control.

If this is a consideration, the choice would be three 11 x 11-

in. plenums.

MAXIMUM UNIT SPACING — Interior zones use less air,

as low as 0.4 to 0.6 cfm per sq ft. Using the large capacity

37HS4 unit at 250 to 350 cfm each may cause units to be too

widely separated. This results in poor coverage and poor air

distribution.

The lowest cost choice would be 9- x 9-in., 9- x 9-in., and

7- x 7-inches.

A good solution is to use a larger number of lower ca-

pacity 37HS2 units at 150 to 190 cfm each.

The maximum distance between units parallel to each other

(blowing at each other) can and should be fairly great, 25 to

45 ft. (See Tables 4 and 5.) But the maximum distance be-

tween the ends of the units in the same row must be more

limited for good coverage.

If the requirement of the space is for maximum cfm from

the unit combination, one of the larger plenum combinations

would be favored.

Conversely, a conservative design with small cfm per unit

can use the smaller plenum sizes.

The unit will effectively cover a strip whose width is 3 to

4 times the unit’s length. A 4-ft unit would therefore cover

an area whose width is 12 to 16 ft (maximum). See

Fig. 18.

The selection of plenum sizes will not affect the sound

level of the space; there is no measurable difference in the

recommended plenum combinations.

The high induction ratio of the Moduline௡ diffuser keeps

total room air motion up to acceptable levels when the cfm

per sq ft is low.

NOTE: The listing of recommended air series combinations

does not indicate that one controller will always handle the

combination; in some cases, a second controller may be re-

quired. Refer to Determine Controller Location section,

page 37.

Table 9 provides an overall limitation on cfm in the inlet

collar of units in air series.

Fig. 18 — Unit Spacing

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Fig. 19 — Run-Out Duct for Single Modulineா Unit

Fig. 20 — Run-Out Duct for Moduline Units in Air Series

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Table 6 — 37HS1 Units in Air Series

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Table 6 — 37HS1 Units in Air Series (cont)

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Table 7 — 37HS2 Units in Air Series

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Table 7 — 37HS2 Units in Air Series (cont)

Table 8 — 37HS4 Units in Air Series

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Table 8 — 37HS4 Units in Air Series (cont)

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Table 9 — Maximum Cfm Through the Inlet Collar

of a Single Unit or of Units in Air Series

In general, units in an air series should not be of mixed

sizes (cfm capacities). If units of different capacities are used,

a controller must be applied for each size unit. For example,

an application for 800 cfm using different capacity units, as

shown in Fig. 21, is acceptable only with multiple controls.

This arrangement, although not preferred, can be used if care

is taken to use the necessary controllers. In this case, 3 con-

trollers are required. However, the best installation for an

800 cfm (nominal cfm total) would be one in which all the

units are the same size. (Fig. 22.) In this case, a single con-

troller can be used in the space.

INLET

PLENUM

SIZE

(in.)

MAXIMUM TOTAL

AIRFLOW

COLLAR

DIAM

MODEL

(Cfm)

(in.)

5 x 7

7 x 7

110

400

37HS1

9 x 9

800

11 x 11

7 x 7

1100

400

37HS2

37HS4

9 x 9

800

11 x 11

9 x 9

1100

800

11 x 11

13 x 13

1100

1600

Fig. 21 — Air Series of Units with Different Capacities

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Fig. 22 — Air Series of Units of the Same Size and Capacity

FLEX DUCT IN AIR SERIES — Flexible duct is often used

minimum static pressure for multiple units is equal to 0.75

in. wg. Three lengths of ﬂex duct at 4.5 ft equal 13.5 ft.

From Table 11, read with 8-in. duct diam, ⌬P is equal to

0.16 in. wg for each 10 ft. of ﬂex duct. Therefore, for

13.5 ft, ⌬P is equal to 0.16 + 0.06 in. wg. The total ⌬P

downstream of run-out duct is equal to 0.75 + 0.22

= 0.97 in. wg.

in air series to connect Moduline௡ units. In calculating pres-

sure requirements for units in air series, use the following

guidelines:

1. For close-coupled units (either continuous diffuser or units

in adjoining ceiling modules) where the ﬂexible duct used

is 6 to 8 in. in length, add 0.1 in. wg to unit requirement

for minimum static pressure at control unit (Table 10).

3. Flexible duct, unsupported, tends to sag; this deﬂection

increases the pressure drop. Whenever possible, support

the duct with wire between connections. Sagging will in-

crease the ⌬P as much as 0.06 in. wg in a 10-ft length;

therefore rigid duct is recommended for lengths greater

than 5.5 ft.

4. The use of ﬂexible duct in air series run-out when 90 de-

gree turns are required will also add ⌬P. Table 12 pro-

vides the additional pressure drop.

For example, consider three 37HS2 units in air series, in

adjoining modules, with 200 cfm per unit (Fig. 23). The

minimum static pressure for multiple units is equal to 0.75

in. wg (from Table 10). Adding 0.1 in. wg for ﬂexible

duct, the total pressure downstream of run-out duct equals

0.85 in. wg.

2. For units in air series with extended ﬂexible duct lengths,

add ⌬P from Table 11.

For example, refer to Fig. 25. The ‘‘straight’’ line ⌬P is

equal to 0.97 in. wg. If a bend is added to the run-out, the

total pressure drop becomes:

For example, consider four 37HS2 units in air series,

200 cfm per unit (Fig. 24). The units are in alternate

series modules; 8-in. duct; 9- x 9-in. plenum. The

0.97 + 0.16 = 1.13 in. wg.

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Table 10 — Minimum Static Pressure at Control

(Master) Unit — Units with System-Powered

Controls and Standard Diffusers

Table 11 — Additional ⌬P for

Extended Lengths of Flexible Duct

FLEX

DUCT

DIAM

(in.)

TOTAL

CFM

ADDITIONAL

⌬P PER

10 FT FLEX DUCT

(in. wg)

37HS1

37HS2

37HS4

IN AIR

SERIES

PLENUM SIZE (in.)

AIRFLOW

(Cfm)

7 x 7

9 x 9

11 x 11

7 x 7

9 x 9

400

800

0.2

5 x 7

11 x 11

13 x 13

0.16

0.1

11 x 11

1100

1600

Minimum Static Pressure (in. wg)

0.07

0.75

N/A

100

0.75

110

0.90

N/A

0.90

N/A

0.75

N/A

Table 12 — Additional ⌬P for

Flexible Duct with 90-Degree Bend

120

140

160

180

200

FLEX

DUCT

DIAM

(in.)

TOTAL

CFM

IN AIR

SERIES

RADIUS

BEND

(in.)

ADDITIONAL ⌬P

FOR 90° BEND

IN FLEXIBLE DUCT

(in. wg)

N/A

0.75

0.90

0.75

220

400

800

0.26

0.16

0.08

0.04

240

280

320

360

400

N/A

0.75

0.90

1100

1600

440

N/A — Not Applicable

NOTE: Maximum inlet pressure — 3.0 in. wg.

C — Controller

Fig. 23 — Three 37HS2 Modulineா Units in Adjoining Modules

Fig. 24 — Four 37HS2 Moduline Units in Alternate Series Modules

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Fig. 25 — Flexible Duct Used with 90-Degree Bend

GUIDELINES FOR CONTROLLER LOCATION

Step 4 — Determine Controller Location — The

ﬁnal step in the terminal selection and layout process is to

decide where the controllers will be placed.

1. A master unit is mounted in the ceiling so that the air

intake is on the end of the unit opposite the end with the

control block and controller. (Fig. 26.)

2. A slave unit can receive air from either end of the unit.

Either end can be the inlet, assuming the inlet collar is

the same size as the connecting unit. At the same time, it

is good practice to place the ‘‘control’’ end of a slave unit

downstream as shown in Fig. 26. Should the slave unit be

later converted to a master unit, the unit would be in its

correct conﬁguration for control installation.

The temperature control zones in the building will be de-

termined by the ﬁnal partition layout. Before the ﬁnal par-

tition layout has been determined, you must install enough

controllers to meet job requirement; the controllers can then

be relocated when the tenant layout is ﬁnished.

One of the main features of Moduline controls is that con-

troller locations can be changed quickly and easily at any

time.

3. The volume controller for a single unit should be located

on the end of the unit opposite the inlet end. (Fig. 27.)

Another main feature of Moduline controls is that more

than one unit can be controlled from a single thermostat. In

large interior zones the ‘‘master’’ unit (the one with the ther-

mostat) can be hooked up with control tubing to control sev-

eral ‘‘slaves’’. Table 13 shows the maximum number of units

that can be controlled by one controller.

Table 13 — Maximum Number of Units in an

Air Series on One Controller

PLENUM

SIZE (in.)

NUMBER OF UNITS ON ONE CONTROLLER

MODEL FIRST UNIT

IN AIR

Units in Air Series

Single

Unit

SERIES*

5 x 7†

—

7 x 7

37HS1

9 x 9

11 x 11

7 x 7

—

37HS2

37HS4

9 x 9

11 x 11

9 x 9

—

11 x 11

13 x 13

*See Tables 6-8 for recommended combinations of units in air series.

†The 37HS1 unit with 5 x 7 size plenum is available with blank end only; mul-

tiple units of this size would not be used on one control.

Fig. 26 — Air Intake on Master Unit

NOTE: The conditions stated in Table 9 must be included in evaluations for

selecting the number of units in an air series.

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4. The controller for units in an air series should be located

as shown in Fig. 28.

5. Volume controllers for units in an air series must be con-

nected from master to slave units in the same air series;

they must not be connected to units in a different air

series from that of the master unit. See examples shown

in Fig. 29 and 30.

C — Controller

6. To connect slave units with control tubing, use the end

bellows ﬁttings only; do not attempt to use the 0.25 molded

connection on the ﬁlter. See Fig. 31 for examples of con-

trol tubing connections.

Fig. 27 — Location of Volume Controller

on Single Unit

C — Controller

Fig. 28 — Location of Volume Controller on Units in an Air Series

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EXAMPLES OF GUIDELINE USE — Figure 29 shows an incorrect application. Figure 30 shows the corrected layout.

An incorrect application:

1. Room A & B units are on the same controller but on different duct

air series.

2. Room B calls for half the cfm as in units in room A — not feasible

because there is only one controller.

3. Units in room C are on different duct runs with one control — not

correct.

4. Units in room D are ﬁne for one control, but controller should be

on second unit in air series.

Fig. 29 — Incorrect Layout of Modulineா Units with Controls

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The corrected layout:

1. Room A has its own controller.

2. Room B has its own controller.

3. Room C has a correct air series for one control.

4. Room D has the controller in the proper location.

Fig. 30 — Corrected Layout

Fig. 31 — Control Tubing Connection

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• the control tube layout for connecting the master unit (with

thermostat) to all its slaves

Final Layout — After these 4 steps are complete, you

are ready to make a ﬁnal layout.

• the cfm for the master unit (all slaves will be the same cfm

and need not be indicated)

The ﬁnal layout should show not only the number and lo-

cation of the Moduline units, but also:

• the model number of the unit to be used

• the round duct size connected to the unit

• the controller location

THE MODULINEா VALVE

Figure 32 shows the Moduline terminal in cross section

with the valve in three positions — shutoff, partially open

and fully open. The valve opening varies with the pressure

of the bellows and the pressure of the plenum.

Figure 33 shows the internal components of the Moduline

unit.

Figure 34 shows the comparison of operating character-

istics between Carrier’s new Moduline unit (the 37HS) and

the previous design.

The Moduline Control Concept — The 37HS Modu-

line system-powered control concept is based on using the

building’s primary air supply as a source of energy. The dis-

tribution duct pressure provides energy to operate the con-

trols that modulate the ﬂow of air through the unit. The heart

of this system is a bellows-operated unit air valve, which is

positioned by varying the pressure of the air in the bellows

relative to the supply air pressure in the duct. As the pres-

sure in the bellows approaches the pressure in the supply

duct, the unit air valve opening is reduced, ﬁnally closing

completely when the pressures are equal.

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UNIT SHUTOFF — BELLOWS FULLY INFLATED

UNIT MODULATING — BELLOWS PARTIALLY INFLATED

UNIT FULL CAPACITY — BELLOWS DEFLATED

Fig. 32 — Bellows and Unit Air Valve Arrangement

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HIGH AND LOW PRESSURE — As primary air ﬂows from

the unit plenum to the unit air valve and from there to the

conditioned space, it passes through a slotted plate called

the distribution baffle. The resistance of the baffle tends to

‘‘even out’’ the airﬂow through the unit. The baffle also cre-

ates a pressure differential which forms the basis of the sens-

ing side of the unit control.

Static pressure from above the baffle is called the high

pressure; static pressure below the baffle is the low pressure.

Figure 35 shows the pick-up tubes for the high and low pres-

sures, the differential pressure across the distribution baffle.

Fig. 33 — Cross Section of 37HS Moduline

Air Terminal

Fig. 34 — Bellows Comparison

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delivers maximum ﬂow, as determined by the existing ple-

num pressure. Units normally operate between these ex-

tremes. In constant volume applications, the bellows pres-

sure is automatically adjusted in proportion to the plenum

pressure, providing a constant pre-set ﬂow within the oper-

ating limits of the unit. In variable air volume op-

eration, the bellows pressure is further modulated to reduce

ﬂow below the preset level as load requirements are satis-

ﬁed. After passing through the valve, the primary air ﬂows

down through the diffuser and out to the conditioned space.

CONTROL APPLICATIONS

Introduction — The Moduline௡ terminal is offered with

a variety of cooling and heating control options which adapt

to many building applications. In this section, the various

control applications are described and the functions they in-

clude are identiﬁed. Each application has a function number

which corresponds to the function number shown in

Tables 14 and 15 in the Control Selection section, page 50.

Table 14 describes the functions; Table 15 shows the control

packages required for each function. The part numbers shown

are found on the Moduline air terminal price pages.

Detailed operating sequences for each control application

are found beginning on page 55.

System-Powered Controls

COMPONENTS OF THE SYSTEM-POWERED CON-

TROL SYSTEM — The 37HS system-powered control con-

sists of a set of custom design and manufacturer’s compo-

nents which provide airﬂow and temperature regulation of a

Moduline air terminal. These devices are interchangeable,

ﬁeld-installed components which plug into the Moduline unit

without the use of tools.

Figure 36 shows the basic components: Control block (part

of the unit); ﬁlter/manifold; volume controller; and thermo-

stat. Figure 37 demonstrates the control air paths in a sec-

tional view of the control system. Note that the high pres-

sure and low pressure pick-ups of the unit are connected through

the control block to the ﬁlter and from there to the volume

controller and thermostat.

Fig. 35 — High and Low Pressure Pick-Up Tubes

BELLOWS PRESSURE — As the airﬂow through the unit

changes, the high and low pressures vary proportionately.

Comparing these 2 pressures, the unit volume controller pro-

vides a bellows pressure which in turn inﬂates the unit air

valve. Bellows pressure varies from near zero at full ﬂow to

plenum or duct pressure at shutoff.

UNIT AIRFLOW DELIVERY — The relationship between

the bellows pressure and the plenum pressure determines the

unit air valve position, which controls unit airﬂow delivery.

When the pressures become nearly equal, the valve closes

and the unit shuts off. Conversely, as the bellows pressure

approaches zero, the valve opens completely and the unit

Figure 38 shows the control ﬁlter/manifold; Fig. 39, the

airﬂow volume controller; Fig. 40, the diffuser thermostat

with aspirator; and Fig. 41, the wall thermostat and alternate

to diffuser mounting.

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Fig. 36 — 37HS Control Components

Fig. 37 — Basic 37HS Control Operation

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Both CV and VAV control packages include a plastic baffle

which is installed over the vertical leg of the center diffuser

and blocks the unused portion of the diffuser slots. See

Fig. 42. On VAV units, this prevents stray air currents from

inﬂuencing thermostat operation.

Other control components used in extended system-

powered electric and pneumatic control schemes are de-

scribed in the control applications which follow.

Fig. 41 — Wall-Mounted Thermostat

Fig. 38 — 37HS Control Filter/Manifold

CFM

120

Fig. 39 — 37HS Airﬂow Volume Controller

Fig. 42 — Diffuser Baffle Assembly

Fig. 40 — Unit-Mounted (Diffuser) Thermostat

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SYSTEM-POWERED APPLICATIONS

VAV Cooling With Warm-Up — (Function 4.) During an ex-

tended off period (overnight or during a holiday), the space

temperature will often be lowered. It is necessary to provide

heated air, temporarily, to reestablish comfortable tempera-

tures when occupancy resumes. Since the cooling thermo-

stats are satisﬁed at the reduced temperature, the units will

be shut off and the system will not be able to deliver warm

air. It is necessary, therefore, to provide a means of tempo-

rarily overriding the cooling thermostat. System-powered

warm-up is achieved by adding a warm-up switch to the VAV

cooling control arrangement (Fig. 45). The warm-up switch,

located inside the unit plenum, closes when it senses that

warm air is being supplied to the unit. This causes the bel-

lows to bleed, opening the unit. This condition is maintained

until cool air is returned to the system and the warm-up switch,

sensing cool supply air, returns control to the thermostat.

Where all Moduline units on a main duct-run are pro-

vided with thermostats for variable air volume control, it is

often difficult to get warm air to the end units on a run; with

the units in shutoff there is no signiﬁcant ﬂow which will

trigger the warm-up switch. Solutions to this situation are

found on page 58 in the Control Operating Sequences, VAV

Cooling with Warm-Up section.

Constant Volume (CV) Cooling — (Function No. 1.) This is

the most basic operating conﬁguration. The control arrange-

ment consists of the volume controller and the ﬁlter. The unit

maintains a steady ﬂow of primary air at the quantity set on

the volume controller over a range of supply pressures. Fig-

ure 43 shows constant volume controls mounted on the Modu-

line௡ unit.

CV Heating (Function No. 1.) Constant volume heating con-

trols are the same as for CV cooling.

Variable Air Volume (VAV) Cooling — (Function No. 2 and

3.) The addition of a cooling thermostat to the constant vol-

ume controls allows the unit to vary the ﬂow of primary air.

The unit will provide just enough airﬂow to satisfy the ther-

mostat setting at existing load conditions, up to the maxi-

mum ﬂow set on the volume controller. The cooling thermo-

stat is direct acting (DA); thus the branch pressure output

from the thermostat increases as the space temperature in-

creases. Both diffuser-mounted and wall-mounted variations

are available. Figure 44 shows the system-powered VAV con-

trols (with diffuser thermostat) mounted on the unit.

Fig. 43 — Constant Volume Control

Arrangement

Fig. 45 — VAV Control Arrangement for

System-Powered Warm-Up

Fig. 44 — Variable Air Volume Control

Arrangement

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SYSTEM-POWERED CONTROLS WITH ELECTRIC

INTERFACE

VAV Heating and Cooling With Changeover — (Function

5.) A VAV control arrangement for cooling/heating includes

a wall-mounted cooling/heating thermostat and provision to

change the thermostat from cooling to heating conﬁguration

and back again. Figure 46 shows the control arrangement

with Moduline௡ control for heating and cooling. The wall

thermostat is shown in Fig. 47. The system-powered heating

and cooling changeover uses an assembly consisting of 2

temperature-operated pneumatic switches located inside the

unit plenum and installed in-line between a cooling/heating

thermostat and the volume controller. These switches se-

quence the thermostat between the cooling and heating modes,

depending upon the temperature of the primary air supply.

VAV Cooling With Electric Warm-Up — (Function 6.) Elec-

tric warm-up uses an electric changeover valve to perform

the same function as system-powered warm-up; that is, to

provide heated air to reestablish comfortable temperatures

when occupancy resumes after an extended unoccupied pe-

riod. Since the cooling thermostats are satisﬁed at the re-

duced temperature, the units will be shut off and the system

will not be able to deliver warm air. It is necessary, there-

fore, to provide a means of temporarily overriding the cool-

ing thermostat.

The changeover control is an electrically operated, re-

motely controlled 3-way solenoid valve. The normally closed

port of the valve is capped. The valve usually is wired to

activate automatically with the supplemental heating switch;

however, it can also be manually activated. This option may

be used with either a unit-mounted or wall-mounted ther-

mostat. See Fig. 49.

VAV Heating — (Function 9.) Variable air volume heating

controls are the same as for VAV cooling except that only a

wall-mounted heating thermostat is offered (Fig. 48). The

heating thermostat is reverse acting (RA); thus the output

pressure decreases as the space temperature increases.

VAV Heating and Cooling With Electric Changeover — (Func-

tion 7.) A VAV control arrangement for cooling/heating in-

cludes a wall-mounted cooling/heating thermostat (Fig. 47)

and provision to change the thermostat from a cooling to

heating conﬁguration and back again. System-powered cooling/

heating with electric changeover uses a 3-way electric so-

lenoid valve to switch control between the cooling and heat-

ing functions of a cooling/heating wall-mounted thermostat.

It is installed in-line between the volume controller of a CV

cooling control package and the thermostat. The valve may

be activated separately or interlocked with an electric heat-

ing system. See Fig. 50.

Fig. 46 — System-Powered Changeover

Switch Arrangement with Heating/Cooling

Wall Thermostat

Fig. 49 — VAV Control Arrangement

for Electric Warm-Up

Fig. 47 — Cooling/Heating Wall Thermostat

Fig. 50 — VAV Control Arrangement

for Electric Changeover

Fig. 48 — Wall-Mounted Heating Thermostat

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VAV Cooling With Electric Heat Interlock — (Function 8.)

In cases where VAV cooling terminals are used in conjunc-

tion with a separate heating system, such as perimeter heat-

ing, it is necessary to prevent the heating equipment from

turning on before the cooling system turns off. The addition

of a differential pressure switch to the unit controls makes

this possible. When the switch detects that control pressures

are approaching a shutoff condition (cooling load satisﬁed),

it closes a set of contacts. This allows the heating system to

operate as the heating thermostat dictates. See Fig. 51.

VAV Cooling With Fire Safety — (Functions 11 and 12.) Code

requirements may specify that air distribution terminals be

open or closed during a ﬁre. For example, in tower construc-

tion there may be a requirement that if a ﬁre begins on one

ﬂoor the terminals on the ‘‘ﬁre ﬂoor’’ must be shut off to

prevent the addition of oxygen to the ﬁre; terminals on the

ﬂoors above and below the ﬁre ﬂoor must be wide open to

ventilate the space. These actions must occur regardless of

the space temperature and the position of the individual duct-

powered thermostats (unit mounted or wall mounted). This

application is effectively the same as the pneumatic warm-up

previously described. In this case, the pneumatic switch is

remotely operated by the ﬁre master control to open the ad-

jacent ﬂoor units. Air supply to units on the ‘‘ﬁre ﬂoor’’ is

interrupted by the use of duct ﬁre-dampers.

Fig. 51 — VAV Control Arrangement with

Electric Heat Interlock

SYSTEM-POWERED CONTROLS WITH PNEUMATIC IN-

TERFACE — The Moduline unit is designed as a stand-

alone, reactive air terminal in which the only source of en-

ergy for control purposes is the distribution air itself. There

are applications where separate system energy affords ad-

ditional control functions not possible with system power.

This section covers the use of 20 psi pneumatic energy and

standard and custom pneumatic devices for the application

of Moduline terminals in a conditioning system.

Fig. 52 — Pilot Valve for Pneumatic Sequenced

Cooling/Heating (Hot Water)

Pneumatic Sequenced Cooling/Heating (Hot Water) — (Func-

tion 10.) A 37HS VAV cooling system can be sequenced with

a hot water heating system through the use of a pilot valve

and a single proportional pneumatic thermostat (one-pipe or

2-pipe). See Fig. 52. By properly matching the operating pres-

sure ranges of the pilot valve and the ﬁeld-supplied hot wa-

ter heat valve, the system can be conﬁgured to automatically

change over from cooling to heating and back again based

on the thermostat branch line pressure. The cooling and heat-

ing functions can be separated by a deadband or they can be

overlapped, depending upon pressure ranges selected. The

system may be designed to use either of the following

combinations:

• pilot valve (NO), hot water valve (NO) and thermostat (DA,

one- or 2-pipe)

• pilot valve (NC), hot water valve (NC), and thermostat (RA,

one- or 2-pipe)

Fig. 53 — VAV Control Arrangement with

Pneumatic Warm-Up Switch

VAV Cooling With Pneumatic Warm-Up — (Functions 11

and 12.) Pneumatic warm-up is accomplished by using a re-

motely operated pneumatic switch in place of the system-

powered warm-up switch. The pneumatic switch is installed

in-line between the volume controller and the thermostat (unit

mounted or wall mounted) and must be closed during

warm-up. It may be either normally open or normally closed,

but must match the pneumatic line pressure available. See

Fig. 53.

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NOTE: The following applications require the control pack-

ages shown for Function 10, plus ﬁeld-supplied thermostats

as described below.

Control Packages — In order to obtain a desired set

of control functions with Moduline air terminals, the correct

combination of control packages is required. Table 15 shows

the control packages that must be installed on a master unit

in order to achieve each function. The control package num-

bers correspond to the numbers on the 37HS Price Pages.

Night Set Back Heating — In the interest of energy conser-

vation, it may be desirable to raise a system’s cooling set

point during unoccupied time periods, whether they occur at

night or on weekends, holidays or other occasions. This ap-

plication requires a ﬁeld-supplied dual set point DA pneu-

matic thermostat operating on a switched-main pressure supply.

The air supply must have 2 pressure levels available. A nor-

mally open pilot valve, controlled by the dual thermostat, is

also required. The thermostat set point is determined by the

supply pressure selected.

VAV Cooling/Separate System Heating —AModuline௡ cool-

ing system may be interlocked with a separate hot water heat-

ing system and controlled by a common thermostat. This ap-

plication requires a ﬁeld-supplied switched-main pressure

supply, a ﬁeld-supplied dual set point DA/RA pneumatic ther-

mostat, a pneumatic switching relay, a pilot valve, and a pneu-

matic hot water valve. The summer mode (cooling) or the

winter mode (heating) is selected by switching the pneu-

matic supply system pressure between high or low pressure

ranges. The pneumatic thermostat operates in either the cool-

ing mode (DA) or the heating mode (RA) depending on the

supply pressure provided. The pneumatic switching relay re-

sponds to the pressure level by selecting either the pilot valve

and the Moduline cooling system or the hot water valve and

the hot water heating system, to match the thermostat mode.

Table 14 — Control Index

FUNCTION

FUNCTION DESCRIPTION

NO.

Cooling or Heating Only, Constant Volume

Cooling Only, Variable Volume, Diffuser Thermostat

Cooling Only, Variable Volume, Wall Thermostat

VAV Cooling with System-Powered Warm-Up,

Wall Thermostat

VAV Cooling/Heating, System-Powered Changeover,

Wall Thermostat

VAV Cooling with Electric Warm-Up, Wall Thermostat

or Diffuser Thermostat

VAV Cooling/Heating, Electric Changeover,

Wall Thermostat or Diffuser Thermostat

VAV Cooling with Electric Heat Interlock

Heating Only, Variable Volume, Wall Thermostat

VAV Cooling with Pneumatic Sequenced Heating (Hot Water)

and Pneumatic Thermostat*

VAV Cooling with Pneumatic Warm-Up or Fire Safety Switch,

Wall Thermostat

VAV Cooling with Pneumatic Warm-Up or Fire Safety Switch,

Diffuser Thermostat

*For night set back heating, a ﬁeld-supplied dual set point DA thermostat must

be used with the control packages and components shown in Table 15. For

VAV cooling/separate system heating, a ﬁeld-supplied dual set point DA/RA

thermostat must be used with the control packages and components shown

in Table 15.

CONTROL SELECTION

Control Index — Table 14 summarizes the control func-

tions available with 37HS Moduline air terminals. These func-

tions are described in detail in the preceding Control Appli-

cations section.

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Table 15 — 37HS Control Combinations

CONTROL

PACKAGES

REQUIRED

NO.

FUNCTION

MODEL

CONNECTION ARRANGEMENT

SYSTEM POWERED

37HS1

37HS2

37HS4

37HS900003

CONSTANT VOLUME

COOLING

SYSTEM POWERED

37HS1

37HS2

37HS4

37HS900001

37HS900002

37HS900004

VARIABLE VOLUME

COOLING

DIFFUSER

THERMOSTAT

SYSTEM POWERED

37HS900003

37CM901012

37HS1

37HS2

37HS4

VARIABLE VOLUME

COOLING

37HS900003

37CM901012

WALL THERMOSTAT

37HS900003

37CM901012

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Table 15 — 37HS Control Combinations (cont)

CONTROL

PACKAGES

REQUIRED

NO.

FUNCTION

MODEL

CONNECTION ARRANGEMENT

SYSTEM POWERED

37HS900003

37CM900152

37CM901012

37HS1

37HS2

37HS4

VARIABLE VOLUME

COOLING

37HS900003

37CM900152

37CM901012

SYSTEM POWERED

WARM-UP

WALL THERMOSTAT*

37HS900003

37CM900152

37CM901012

SYSTEM POWERED

37HS900003

37CM900192

37CM900992

37HS1

37HS2

37HS4

VARIABLE VOLUME

HEATING & COOLING

37HS900003

37CM900192

37CM900992

SYSTEM POWERED

CHANGEOVER

WALL THERMOSTAT

37HS900003

37CM900192

37CM900992

SYSTEM POWERED

37HS900003

37CM900792†

37CM901012

37HS1

37HS2

37HS4

VARIABLE VOLUME

COOLING

37HS900003

37CM900792†

37CM901012

ELECTRIC WARM-UP

WALL THERMOSTAT*

37HS900003

37CM900792†

37CM901012

*To use a diffuser thermostat in place of the wall thermostat, replace constant volume package 37HS900003 and wall thermostat 37CM901012

with variable volume package 37HS900001 (37HS1), 37HS900002 (37HS2) or 37HS900004 (37HS4).

†Package 37CM900792 is 24 v; other voltages available.

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Table 15 — 37HS Control Combinations (cont)

CONTROL

NO.

FUNCTION

MODEL

37HS1

37HS2

37HS4

PACKAGES

REQUIRED

CONNECTION ARRANGEMENT

SYSTEM POWERED

37HS900003

37CM900792†

37CM900992

VARIABLE VOLUME

HEATING & COOLING

37HS900003

37CM900792†

37CM900992

ELECTRIC CHANGEOVER

WALL THERMOSTAT

37HS900003

37CM900792†

37CM900992

SYSTEM POWERED

37HS900001

37CM900922

37HS1

37HS2

37HS4

VARIABLE VOLUME

COOLING

37HS900002

37CM900922

DIFFUSER THERMOSTAT**

37HS900004

37CM900922

ELECTRIC

INTERLOCK TO FAN COIL

OR BASEBOARD HEATING

SYSTEM POWERED

37HS900003

37CM901002

37HS1

37HS2

37HS4

VARIABLE VOLUME

HEATING

37HS900003

37CM901002

WALL THERMOSTAT

37HS900003

37CM901002

†Package 37CM900792 is 24 v; other voltages available.

**To use a wall thermostat in place of the diffuser thermostat, replace variable volume packages 37HS900001 (37HS1), 37HS900002 (37HS2) or

37HS900004 (37HS4) with constant volume package 37HS900003 and add wall thermostat 37CM901012.

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Table 15 — 37HS Control Combinations (cont)

CONTROL

PACKAGES

REQUIRED

NO.

FUNCTION

MODEL

CONNECTION ARRANGEMENT

SYSTEM POWERED

37HS900003

37CM900972 (NO)

with

VARIABLE VOLUME

COOLING

37HS1

37HS2

37HS4

37HS900007 (DA)

PNEUMATIC

PILOT VALVE FOR

HEATING/COOLING

SEQUENCE

37CM900982 (NC)

with

37HS900008 (RA)

37HS900003

PNEUMATIC

WALL

THERMOSTAT††

37CM900972 (NO)

with

37HS900007 (DA)

37CM900982 (NC)

with

37HS900008 (RA)

37HS900003

37CM900972 (NO)

with

37HS900007 (DA)

37CM900982 (NC)

with

37HS900008 (RA)

SYSTEM POWERED

37HS900003

37CM901012

37HS900017

37HS1

37HS2

37HS4

VARIABLE VOLUME

COOLING

37HS900003

37CM901012

37HS900017

WALL THERMOSTAT

PNEUMATIC

WARM-UP/FIRE

SWITCH

37HS900003

37CM901012

37HS900017

SYSTEM POWERED

37HS900001

37HS900017

37HS1

37HS2

37HS4

VARIABLE VOLUME

COOLING

37HS900002

37HS900017

DIFFUSER

THERMOSTAT

37HS900004

37HS900017

PNEUMATIC

WARM-UP/FIRE

SWITCH

††For night set back heating, a ﬁeld-supplied dual set point DA ther-

mostat must be substituted for thermostat packages shown. For

VAV Modulineா cooling/separate system heating, a ﬁeld-supplied

dual set point DA/RA thermostat must be substituted for thermo-

stat packages shown.

LEGEND

Direct Acting

Normally Closed

—

Normally Open

Reverse Acting

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The control valve is positioned by 2 diaphragms, one in

the low pressure chamber and one in the high pressure cham-

ber, and an adjustable spring. Pressure above the low pres-

sure diaphragm tends to open the control valve while the

high pressure diaphragm tends to hold it closed. The spring

tension balances these forces as the pressures vary and de-

termines the valve position. Rotating the adjusting dial on

the volume controller changes the spring tension and pro-

vides a means of establishing a ﬂow set point.

CONTROL OPERATING SEQUENCES

System-Powered Controls

CV COOLING — See Fig. 54. Air from above the distri-

bution baffle (high pressure) enters the ﬁlter through the up-

per port of the control block, while the lower port receives

air from below the baffle (low pressure). These air streams

pass through separate ﬁlter chambers where particulate con-

taminants are removed.

The bellows pressure determined by the action of the con-

trol valve is communicated to the bellows. As the plenum

pressure changes, the control bellows valve is constantly re-

set to maintain a corresponding bellows pressure. The bel-

lows pressure chamber of the volume controller feeds air back

through the middle port and chamber of the ﬁlter (also called

a bellows pressure chamber), to the bellows connection on

the unit end panel, and into the bellows. The bellows pres-

sure re-sets the bellows on the unit air valve to provide a

constant airﬂow through the unit at the value selected on the

volume controller dial.

The low pressure air stream enters the low pressure cham-

ber of the volume controller from the top port of the ﬁlter,

while the bottom port of the ﬁlter feeds the high pressure

stream into the controller’s high pressure chamber.

Air from the high pressure chamber feeds into the bellows

pressure chamber of the controller through the ﬁxed oriﬁce.

Pressure in the bellows chamber of the volume controller is

determined by the relationship between the entering ﬂow re-

sistance of the ﬁxed oriﬁce and the leaving ﬂow resistance

of the control valve variable oriﬁce.

As the control valve opens, its resistance decreases and

relatively more air is allowed to bleed, lowering the pressure

in the bellows chamber. As the control valve closes, the ef-

fect is reversed, increasing the bellows pressure. This is the

principle of control by matched oriﬁces.

CV HEATING — Control arrangements and operation are

the same for CV heating as for CV cooling. The controls and

their operation are not affected by the temperature of the sup-

ply air.

Fig. 54 — Constant Volume Controls — Controller Bleeding, Unit Supplying Air

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VAV COOLING — In VAV operation, the ﬁlter and volume

controller perform the same functions as in CV operation.

The unit-mounted thermostat modiﬁes control operation as

described below.

raising the pressure in the low pressure chamber of the con-

troller. As the low pressure rises, it gradually overcomes

the high pressure and opens the bellows pressure-chamber

bleed valve, lowering the bellows pressure proportionally.

This allows the unit damper to open and gradually increase

the ﬂow of conditioned primary air into the space. See

Fig. 56.

This process continues until the ﬂow of primary air is suf-

ﬁcient to offset the load, or until the ﬂow level set point of

the volume controller is reached (Fig. 57). At this point, the

thermostat bleed is closed and the unit is actually operating

in CV conﬁguration. As the load is reduced, the process is

reversed and the unit ﬂow decreases proportionally until the

unit is shut off when the thermostat is satisﬁed (bleed fully

open) (Fig. 58). In this manner, the unit normally delivers

only the actual amount of primary air needed to offset the

existing load.

Refer to Fig. 55. The air enters the low pressure chamber

of the volume controller through a ﬁxed oriﬁce. The low pres-

sure chamber is connected through a stub ﬁtting and tube to

the unit-mounted thermostat. The thermostat senses room tem-

perature, closes its port as the temperature rises, and opens

it as the temperature falls. This makes it possible to control

the pressure in the low pressure chamber in response to the

space temperature. With normal space temperatures, and the

thermostat satisﬁed, the low pressure chamber valve is open

to the atmosphere through the thermostat. The rate at which

the valve bleeds air from the low pressure chamber is high

in relation to the rate at which air enters through the oriﬁce,

and the pressure decreases in relation to the high pressure.

The high pressure force is stronger than the low pressure

force and the bleed valve of the bellows pressure chamber of

the controller is held closed. Since no air escapes, the bel-

lows pressure becomes equal to the high pressure in the ple-

num and the unit damper is closed, shutting off the unit.

When the wall-mounted DA thermostat is used in place of

the unit-mounted thermostat, variable air volume control op-

eration is the same as described above for the unit-mounted

thermostat. The only difference is that the wall-mounted ther-

mostat does not include the aspiration feature.

As the room load increases, the space temperature in-

creases. The thermostat senses this change and starts to close,

Fig. 55 — Variable Volume Controls Schematic

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Fig. 56 — Variable Volume Controls — Minimum Flow: Thermostat Partially Open,

Controller Partially Open, Unit Delivering Minimum Flow

Fig. 57 — Variable Volume Controls — Full Cooling, Thermostat Closed, Controller Bleeding,

Unit Supplying Air

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Fig. 58 — Variable Volume Controls — Thermostat Open,

Controller Shut Off, Unit Shut Off

VAV COOLING WITH WARM-UP — Including the warm-

condition will continue as long as air in the duct system re-

mains at a temperature higher than approximately 80 F. As

the supply air returns to normal cooling temperatures, the

switch opens and control is returned to the cooling thermo-

stat. See Fig. 60.

fup switch in the volume controller/thermostat circuit al-

lows the unit to deliver air when there is warm air in the duct

system, even though the cooling thermostat is satisﬁed by

cool space temperature.

The warm-up switch is actually a temperature controlled

pneumatic valve which is normally open at primary air sup-

ply temperatures below approximately 64 F. It is installed

in-line between the volume controller and the thermostat.

When warm primary air is supplied to restore comfort con-

ditions in the space after an extended shutdown, the warm-up

switch reacts by closing (Fig. 59). This removes the ther-

mostat from the control circuit and prevents air from bleed-

ing from the low pressure chamber of the volume controller.

This condition simulates a thermostat calling for maximum

primary-air delivery. The unit is now, in effect, a CV unit

and operates at the set point of the volume controller. This

Because the units are shut off, it may be difficult to es-

tablish the ﬂow of warm air to initiate warm-up. One method

of overcoming this problem is to install one or more CV units

near the end of the duct run. Where possible, a constant vol-

ume unit is located in space not continuously occupied such

as halls, aisles, or storage rooms. It can also be helpful in an

area beneﬁting from continuous circulation. By locating such

a unit at the end of a duct run, the heated air for morning

warm-up is assured of reaching the VAV units. See Fig. 61.

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Fig. 59 — Cooling with Warm-Up — Morning, Hot Air in Duct, Warm-Up Switch Closed,

Controller Bleeding, Unit Heating

Fig. 60 — Cooling with Warm-Up — Nighttime Condition, Room Cool, Thermostat Open,

Bleeding, Warm-Up Open, Controller Shut Off, Unit Shut Off

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Fig. 61 — Location of CV Unit for Warm-Up Application

VAV HEATING AND COOLING WITH SYSTEM-

making control air available to each valve. The valve for the

DA cooling thermostat is normally open as long as there is

cool supply air in the plenum (Fig. 62). The other valve is

normally open when warm air is being supplied, matching

the RA heating thermostat (Fig. 63). Each valve is con-

nected to the corresponding thermostat by a separate tube.

In the cooling mode (Fig. 64), the cooling valve is open,

activating the cooling thermostat, while the heating thermo-

stat is isolated by the closed heating valve. On changeover

from cooling to heating, the cooling valve closes and the

heating valve opens, shifting control to the heating thermo-

stat (Fig. 65).

POWERED CHANGEOVER — This application uses a CV

control package along with a wall-mounted thermostat pack-

age (cooling/heating) and a system-powered changeover con-

trol package. The cooling thermostat is direct acting (DA)

while the heating thermostat is reverse acting (RA).

Operation is very similar to system-powered warm-up. The

changeover switch assembly is ﬁeld installed in the unit ple-

num and is piped in-line between the volume controller and

the thermostat. It consists of 2 thermally operated pneumatic

valves, one for each thermostat. The tube from the volume

controller is connected by a ‘T’ into the valve assembly,

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Fig. 62 — Heating/Cooling Unit — Cooling, Cold Air in Duct, Changeover in Cooling,

Thermostat Open, Controller Shut Off, Unit Shut Off

Fig. 63 — Heating/Cooling Unit — Heating, Hot Air in Duct, Changeover in Heating,

Thermostat Open, Controller Shut Off, Unit Shut Off

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Fig. 64 — Heating/Cooling Unit — Cooling, Cold Air in Duct, Changeover in Cooling,

Thermostat Closed, Controller Bleeding, Unit Cooling

Fig. 65 — Heating/Cooling Unit — Heating, Hot Air in Duct, Changeover in Heating,

Thermostat Closed, Controller Bleeding, Unit Heating

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VAV HEATING — It is suggested that the following section

be reviewed before reading this section: VAV Cooling,

page 56.

Combining a diffuser-mounted constant volume control pack-

age with a wall-mounted thermostat package (heating only)

allows the use of Moduline௡ units in VAV heating

applications.

The operation of the heating only thermostat is opposite

to that of the cooling only thermostat in that the heating only

thermostat is reverse acting (RA) instead of direct acting (DA).

The thermostat’s bleed valve is open when the room tem-

perature is above set point. It bleeds air from the low

pressure chamber of the volume controller, lowering its pres-

sure, and allowing the relatively stronger pressure of the air

in the controller’s high pressure chamber to hold closed the

bleed from the controller’s bellows pressure chamber. The

bellows pressure becomes equal to the high pressure in the

unit plenum, closing the unit damper and shutting off the

unit discharge. See Fig. 66.

As the room temperature falls, the thermostat bleed closes

proportionally. This raises the pressure of the air in the low

pressure chamber of the controller, forcing the bellows pres-

sure chamber bleed open and lowering the bellows pressure

proportionally. The damper opens and the unit delivers air to

meet the existing demand in the conditioned space.

See Fig. 67.

Fig. 66 — Variable Volume Controls — Thermostat Open, Controller Shut Off, Unit Shut Off

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Fig. 67 — Variable Volume Controls — Minimum Flow: Thermostat Partially Open,

Controller Partially Open, Unit Delivering Minimum Flow

be connected to the warm-up terminal of the central station

System-Powered Controls with Electric

Interface

unit, if such is provided. Thus, when heated air be-

gins to ﬂow in the distribution duct, the bellows is bled down

by the action of the electric warm-up valve and heated air

can ﬂow into the conditioned space (Fig. 68).

VAV COOLING WITH ELECTRIC WARM-UP — Another

approach to warm-up is the addition of an electric warm-up

valve; the operating principle is the same as system powered

warm-up. A building with its conditioning system shut down

during unoccupied hours must be brought close to operating

temperature before the occupants arrive. Heated air supplied

to the space from a central unit can quickly restore operating

conditions. But because the VAV thermostat has closed the

unit, the result of the lack of load, the system powered con-

trol needs to be overcome.

An electric warm-up valve located on the Moduline unit

between the volume controller and the thermostat is wired to

the primary air source machine room. The valve can be

activated by a simple manual or timer switch or it can

In the cooling mode (Fig. 69), air ﬂows freely between

the volume controller and the thermostat and control func-

tion is not affected. When warm-up is activated, the nor-

mally open port closes and the control circuit is closed after

the volume controller. As with system powered warm-up,

this causes the pressure to rise in the low pressure chamber

of the volume controller and opens the valve that bleeds air

from the bellows pressure chamber. The increased bleed rate

lowers the bellows pressure, opening the unit damper, and

allowing the ﬂow of primary air to increase up to the con-

stant volume set point of the volume controller.

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Fig. 68 — Cooling with Warm-Up — Morning, Hot Air in Duct, Warm-Up Switch Closed,

Controller Bleeding, Unit Heating

Fig. 69 — Cooling with Warm-Up — Nighttime Condition, Room Cool, Thermostat Open,

Bleeding, Warm-Up Open, Controller Shut Off, Unit Shut Off

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VAV HEATING AND COOLING WITH ELECTRIC

CHANGEOVER — This application uses a CV control pack-

age along with a wall-mounted thermostat package (cooling/

heating) and an electric changeover package. The change-

over valve permits control of the unit to be switched between

the cooling and heating sides of a cooling/heating thermo-

stat. It is ﬁeld-installed in-line between the volume control-

ler and the thermostat.

controller and the cooling side of the thermostat. Because

the NC port is closed, the heating side of the thermostat is

locked out of the system. Upon changeover to heating, the

solenoid valve is energized. The NO port closes and the NC

port is opened, and the control circuit switches to the heat-

ing side of the thermostat. Typically, the solenoid valve is

wired to activate automatically when the heating system is

turned on, although it may be operated by a simple on/off

switch.

Refer to Fig. 70-73. In cooling operation, the NO port of

the valve opens the control circuit between the volume

Fig. 70 — Heating/Cooling Unit — Cooling, Cold Air in Duct, Electric Changeover in Cooling,

Thermostat Open, Controller Shut Off, Unit Shut Off

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Fig. 71 — Heating/Cooling Unit — Heating, Hot Air in Duct, Electric Changeover in Heating,

Thermostat Open, Controller Shut Off, Unit Shut Off

Fig. 72 — Heating/Cooling Unit — Cooling, Cold Air in Duct, Electric Changeover in Cooling,

Thermostat Closed, Controller Bleeding, Unit Cooling

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Fig. 73 — Heating/Cooling Unit — Heating, Hot Air in Duct, Electric Changeover in Heating,

Thermostat Closed, Controller Bleeding, Unit Heating

VAV COOLING WITH ELECTRIC HEAT INTERLOCK —

A conditioned space may contain a Moduline system for cool-

ing and a separate heating system such as baseboard electric

or hot water or an overhead fan coil. The electric interlock

switch enables the cooling and heating systems to operate as

the load dictates with overlap.

The electric interlock switch compares the bellows pres-

sure with the low pressure, as a practical means of detecting

the operating level of the unit. When the unit is delivering,

the bellows pressure is signiﬁcantly lower than the low pres-

sure and the electric interlock (differential pressure) switch

is open, interrupting the power supply to the heating system.

When the unit is shut off, the pressures are approximately

equal and the switch closes, allowing the heating system to

be energized. It is ﬁeld installed with the low pressure port

piped to the auxiliary bellows pressure stub of the ﬁlter. (See

Fig. 74.) The high pressure port is connected by a ‘‘T’’ into

the line between the volume regulator and the thermostat.

Fig. 74 — Connection for Electric Interlock

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System-Powered Controls with Pneumatic

Interface

PNEUMATIC SEQUENCED HEATING/COOLING (HOT

WATER) — By using a 20 psi pneumatic source, one ther-

mostat can control both heating and Moduline cooling in the

conditioned space. The pneumatic circuit is interfaced with

the system-powered circuit by use of a pilot valve. In cool-

ing, the Moduline airﬂow is controlled by the duct-powered

volume controller just as in all system-powered control. As

the schematic diagram shows, a DA pneumatic wall ther-

mostat working through the pilot valve, replacing the system-

powered thermostat, modulates the pilot valve and thus the

volume controller low side pressure.

Figure 75 shows the piping diagram. Figure 76 shows the

sequence diagram for a direct acting thermostat with a nor-

mally open pilot valve. With the system shut down and the

space temperature low, at start-up the thermostat branch pres-

sure is low, and the normally open water valve (or other heat-

ing means) is open. As the space temperature rises, the branch

pressure rises, modulating the water valve to a closed po-

sition. The pilot valve is normally open, with set point above

water valve spring rate, thus maintaining a low pressure in

the low side of the volume controller, closing the bleed valve

in the controller and raising the bellows pressure to the duct

pressure level; this results in unit shutoff.

Fig. 76 — Sequence Diagram — DA Thermostat

If the space temperature continues to rise, the NO pilot

valve will modulate toward closed, raising the low side pres-

sure, opening the bleed, reducing the bellows pressure, and

opening the Moduline unit air valve. The airﬂow will rise

until the volume controller setting is reached.

Note that the spring rates of the hot water valve and the

pilot valve must be properly matched to accomplish the ac-

tion described above.

A heating/cooling sequence can also be accomplished with

a reverse acting circuit (Fig. 77 and 78). At start-up, the tem-

perature is low, the branch pressure is high, and normally

closed water valve is wide open. As the space temperature

rises, the branch pressure falls and the water valve closes,

stopping the heating supply. The pilot valve is NC and thus

at branch pressures above its setting will open, volume con-

troller low pressure will be reduced, the bellows pressure

will rise and the unit will shut off.

Fig. 77 — Piping Diagram, Heating/Cooling

Sequence, RA Thermostat

LEGEND FOR FIG. 75 - 78

—

Direct Acting

Hot Water

Main

—

Normally Closed

Normally Open

Reverse Acting

Fig. 78 — Sequence Diagram, RA Thermostat

Fig. 75 — Piping Diagram, Heating/Cooling

Sequence, DA Thermostat

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VAV COOLING WITH PNEUMATIC WARM-UP OR FIRE

SAFETY SWITCH — Through the use of a speciﬁc pneu-

matic switch, the functions of pneumatic warm-up and ﬁre

safety can be added to Moduline௡ installations.

Pneumatic warm-up offers an opportunity to open all Modu-

line units in an area to allow immediate hot air distribution

prior to the building occupancy. Through the use of a sepa-

rate pneumatic signal, the pneumatic warm-up switch, placed

in-line between the Moduline volume controller and the dif-

fuser or wall system powered thermostat, closes the low pres-

sure bleed in the thermostat line (in the same way as the

system powered warm-up switch). This raises the low side

pressure, opens the volume controller bleed and lowers the

bellows pressure, allowing airﬂow from the Moduline ter-

minal at the setting of the volume controller.

The pneumatic warm-up switch can be piped either NO or

NC. Figure 79 shows an NO arrangement. The switch is non-

adjustable and preset to close at 8 ± 2.0 psig. Thus a signal

pressure in excess of 10 psi will cause the switch to close.

A pneumatic warm-up switch is required for each Moduline

unit but only one pneumatic signal valve is required for mul-

tiple Moduline units. Figure 80 shows the basic piping.

Fig. 79 — Piping Diagram, NO Conﬁguration,

Pneumatic Warm-Up

The ﬁeld-supplied 3-way pneumatic valve is supplied with

main pressure and is closed in cooling operation. When heat

for warm-up is required, a signal sent from the heat source

opens the pneumatic valve, supplying main pressure to the

Moduline pneumatic warm-up switches. When the heat is

discontinued, the pneumatic valve opens and the switches

return to an open conﬁguration.

Note that the pneumatic warm-up switch is a nonbleed

device. The pneumatic valve should therefore be a 3-way

device, arranged to bleed out the pneumatic circuit down-

stream of the valve when the valve is closed.

The pneumatic warm-up switch can be arranged as an NC

device; Fig. 81 gives the piping connections.

For ﬁre safety, the same switch is added to the Moduline

control circuit as a normally open ﬁre safety switch as shown

in Fig. 82A. The ﬁre safety switch on each Moduline ter-

minal is connected to a pneumatic distribution circuit on each

ﬂoor of the building. A3-way valve is connected to the switches

and to the ﬁre master control as shown in Fig. 83.

The operation is identical to the pneumatic warm-up cir-

cuit. At the onset of a ﬁre, the ﬁre master control opens the

Moduline units on the non-ﬁre ﬂoors by closing the Modu-

line ﬁre safety switches, raising the controller low side pres-

sure and bleeding the bellows. The 3-way pneumatic valve

on each ﬂoor supplies pneumatic pressure in excess of the

set point of 8.0 ± 2 psig. On the ﬁre ﬂoor where air is to be

shut down, the distribution system uses a duct ﬁre-damper

to stop the air, and the ﬁre safety switch position is not the

determining factor in the Moduline operation.

Fig. 80 — Basic Piping for Pneumatic

Warm-Up Switch

If a normally closed ﬁre switch is required, see piping dia-

gram shown in Fig. 82B. In this case, pneumatic pressure is

maintained on the ﬁre switch when the system fan is acti-

vated. Loss of pneumatic pressure closes the ﬁre switch, bleed-

ing the bellows.

Fig. 81 — Piping Diagram, NC Conﬁguration,

Pneumatic Warm-Up

LEGEND FOR FIG. 79 - 83

—

Hot Water

Main

Normally Closed

—

Normally Open

Switch

Thermostat

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AIRFLOW ADJUSTMENT

Each 37HS volume controller is equipped with a maxi-

mum cfm lever for setting the required unit airﬂow in the

ﬁeld. The lever is located at the bottom of the controller. See

Fig. 84. The controller has a star wheel located at the top of

the controller for setting the minimum airﬂow. The star wheel

is also shown in Fig. 84.

Maximum Airﬂow (Cfm) Adjustment — The 37HS

maximum airﬂow adjustment lever is common to all sizes

and is divided into levels of percent cfm. Table 16 shows the

unit airﬂow that will be obtained by each lever setting for

each unit size.

Table 16 — Maximum Airﬂow Settings

Fig. 82A — NO Conﬁguration for Fire Safety

UNIT AIRFLOW (CFM)

37HS2

LEVER SETTING

(% CFM)

37HS1

37HS4

120

100

120

100

240

200

160

480

400

320

160

The maximum cfm is the unit airﬂow obtained when the

thermostat is calling for full cooling in a VAV system; it is

the design cfm for the space conditioned by the unit or units

regulated by one controller.

To set maximum cfm with zero minimum cfm:

1. Set diffuser or wall thermostat for maximum cooling.

2. Turn the minimum cfm star wheel counterlockwise until

the internal stop is reached. Do not attempt to override

stop. (Minimum cfm has been set at zero, and the unit

will turn off when required.)

3. Adjust maximum cfm lever to desired percent cfm.

Fig. 82B — NC Conﬁguration for Fire Safety

Minimum Airﬂow (Cfm) Adjustment — Some ap-

plications require both a design maximum cfm and a mini-

mum cfm. The 37HS controller can be set to provide both

airﬂow requirements.

To set maximum and minimum cfm:

1. Set diffuser or wall thermostat for maximum cooling.

2. Turn the minimum cfm star wheel counterclockwise un-

til the internal stop is reached. Do not attempt to override

stop.

3. Shut off unit by adjusting thermostat to zero cool-

ing, or disconnect tube from volume controller to

thermostat.

4. Place a standard airﬂow hood against the outlet of the

master unit and slowly turn the minimum cfm star wheel

on the controller clockwise until the desired minimum cfm

is reached.

5. Return the thermostat to the desired setting and/or recon-

nect tube between volume controller and thermostat.

Fig. 83 — Fire Safety Switch Floor Layout

6. Adjust maximum cfm lever to desired percent cfm.

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OPEN

MINIMUM CFM

STAR WHEEL

120

CFM

120

100

MAXIMUM CFM LEVER

VOLUME CONTROLLER

Fig. 84 — Minimum and Maximum Airﬂow Adjustments, 37HS Controller

Table 17 — Multiple Unit Airﬂow Variation

Variation in Maximum Airﬂow — As explained in

the Terminal Selection and Layout section, Moduline௡ units

in air series can be controlled individually with a volume

controller at each unit, or with a master/slave combination,

where one controller is used with multiple units. All

the units on one controller must be of the same model

(capacity).

In master/slave combinations, some variation in maxi-

mum airﬂow among the terminals in air series will occur.

The variation in maximum airﬂow is a function of the unit

plenum size, the model, and the number of units in an air

series on one controller. Table 17 shows the expected varia-

tion from the unit with the smallest airﬂow to the unit with

the largest airﬂow.

APPROXIMATE AIRFLOW VARIATION (Cfm)

LOWEST UNIT TO HIGHEST UNIT IN AIR SERIES*

PLENUM

MODEL

Number of Units in Air Series On

One Controller

SIZE (in.)

7 x 7

9 x 9

—

37HS1

37HS2

37HS4

11 x 11

7 x 7

9 x 9

11 x 11

9 x 9

11 x 11

13 x 13

For single units with controller, the cfm variation from

the lever setting is ± 10%.

*Values shown are based on a typical short, straight duct run be-

tween units. Variation shown may be affected if there are excessive

duct pressure losses between units.

NOTE: The variation value shown in Table 17 for a given number of

units of a certain model size (capacity) is the same for all size ple-

nums used in an air series of recommended combinations for that

model size. Thus, 3 units of model size 37HS2, plenum size 9 x 9, will

have a maximum variation of 30 cfm; 3 units, plenum sizes 9 x 9 (2)

and 7 x 7 (1) will also have a maximum variation of 30 cfm. A dash

indicates that the quantity of a particular plenum size is not recom-

mended in air series for that unit size.

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A variety of diffuser assemblies are available for the Modu-

line unit. Tables 18 - 20 show the standard diffusers avail-

able, which can be ordered directly from the price pages.

Tables 21-23 show the optional diffusers, which can be pro-

vided by quote control.

The difference in standard 37HS diffusers and optional 37A

diffusers is demonstrated in Fig. 87. The slot opening in the

37HS is larger than that of the 37A, reducing the net pres-

sure required from the unit and somewhat reducing the throw.

Note that the dimensions of the diffuser shown in Fig. 87

are useful when matching units or 35BD boot diffusers in

the ceiling. Certiﬁed dimension drawings are available for

these diffusers and the other optional diffusers shown in

Tables 21-23.

AIR DISTRIBUTION

Linear slot diffusers are an integral part of the Moduline

unit. They provide excellent air distribution for the condi-

tioned space. The diffuser conﬁguration is designed to in-

duce room air, creating continuous air motion for occupants

of the room and reasonably consistent temperatures from floor

to ceiling.

Figure 85 shows how cool primary air discharged at the

ceiling line induces room air toward the diffuser. The cool

air mixes with the room air, creating room air motion and

raising the temperature of the air descending upon the room

occupants. Figure 86 provides a typical room air distribution

pattern for 2-way blow and one-way blow Moduline units.

The upper number on the distribution pattern is the mixture

temperature; the lower number is the air velocity in ft/min.

Fig. 85 — Modulineா Diffuser Mixing Room Air and Primary Air

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37HS — 2-WAY BLOW

37HS2 — ONE-WAY BLOW

Fig. 86 — Typical Room Air Distribution Pattern

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Fig. 87 — Slot Openings in Standard and Optional Diffusers

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Table 18 — Standard Diffusers for 37HS1

UNIT

MODEL

LENGTH

(in.)

CEILING

TYPE

DESIGNATION

CONFIGURATION

FLOW

MATERIAL

MODE

T-Bar

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

22.92

46.92

2-Way

Alum

Cooling

23.38

47.38

1174 mm

1200 mm

T-Bar

22.92

46.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

One-Way

Alum

Steel

Cooling

23.38

47.38

1174 mm

1200 mm

22.92

T-Bar

Tegular T-Bar

Continous T-Bar

Narrow T-Bar

Two-Way

One-Way

Heating

Cooling

37HS1

DIRECTOR DIFFUSER

23.38

22.92

46.92

Plaster, Spline

2-Way

Cooling

23.38

47.38

1174 mm

1200 mm

REMOVABLE DIFFUSER

Metric

22.92

46.92

Plaster, Spline

2-Way

Alum

Cooling

23.38

47.38

1174 mm

1200 mm

Metric

REMOVABLE DIFFUSER

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Table 19 — Standard Diffusers for 37HS2

UNIT

MODEL

LENGTH

(in.)

CEILING

TYPE

DESIGNATION

CONFIGURATION

FLOW

MATERIAL

MODE

T-Bar

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

46.92

58.92

2-Way

Alum

Cooling

47.38

59.38

1174 mm

1200 mm

T-Bar

46.92

58.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

One-Way

Alum

Steel

Alum

Cooling

47.38

59.38

1174 mm

1200 mm

T-Bar

46.92

58.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

2-Way

One-Way

Heating

Cooling

37HS2

47.38

59.38

1174 mm

1200 mm

DIRECTOR DIFFUSER

46.92

58.92

Plaster, Spline

2-Way

Cooling

47.38

59.38

1174 mm

1200 mm

REMOVABLE DIFFUSER

Metric

46.92

58.92

Plaster, Spline

2-Way

Cooling

47.38

59.38

1174 mm

1200 mm

Metric

REMOVABLE DIFFUSER

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Table 20 — Standard Diffusers for 37HS4

UNIT

MODEL

LENGTH

(in.)

CEILING

TYPE

DESIGNATION

CONFIGURATION

FLOW

MATERIAL

MODE

T-Bar

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

46.92

58.92

2-Way

Alum

Cooling

47.38

59.38

1174 mm

1200 mm

T-Bar

46.92

58.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

One-Way

Alum

Steel

Alum

Cooling

47.38

59.38

1174 mm

1200 mm

T-Bar

46.92

58.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

2-Way

One-Way

Heating

Cooling

37HS4

47.38

59.38

1174 mm

1200 mm

DIRECTOR DIFFUSER

46.92

58.92

Plaster, Spline

2-Way

Cooling

47.38

59.38

1174 mm

1200 mm

REMOVABLE DIFFUSER

Metric

46.92

58.92

Plaster, Spline

2-Way

Cooling

47.38

59.38

1174 mm

1200 mm

REMOVABLE DIFFUSER

Metric

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Table 21 — Optional Diffusers for 37HS1

UNIT

MODEL

LENGTH

(in.)

CEILING

TYPE

DESIGNATION

CONFIGURATION

FLOW

MATERIAL

MODE

T-Bar

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

22.92

46.92

2-Way

Alum

Cooling

23.38

47.38

1174 mm

1200 mm

T-Bar

22.92

46.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

One-Way

Alum

Cooling

23.38

47.38

1174 mm

1200 mm

37HS1

Metric

T-Bar

22.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

T-Bar

2-Way

One-Way;

2-Slot

Heating

Cooling

Alum

23.38

22.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

2-Way

One-Way;

3-Slot

Heating

Cooling

Alum

23.38

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Table 22 — Optional Diffusers for 37HS2

UNIT

MODEL

LENGTH

(in.)

CEILING

TYPE

DESIGNATION

CONFIGURATION

FLOW

MATERIAL

MODE

T-Bar

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

46.92

58.92

2-Way

Alum

Cooling

47.38

59.38

1174 mm

1200 mm

T- Bar

46.92

58.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

One-Way

Alum

Cooling

47.38

59.38

1174 mm

1200 mm

37HS2

T-Bar

46.92

58.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

2-Way

One-Way;

2-Slot

Heating

Cooling

47.38

59.38

1174 mm

1200 mm

DIRECTOR DIFFUSER

T-Bar

46.92

58.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

2-Way

One-Way;

3-Slot

Heating

Cooling

47.38

59.38

1174 mm

1200 mm

DIRECTOR DIFFUSER

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Table 23 — Optional Diffusers for 37HS4

UNIT

MODEL

LENGTH

(in.)

CEILING

TYPE

DESIGNATION

CONFIGURATION

FLOW

MATERIAL

MODE

T-Bar

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

46.92

58.92

2-Way

Alum

Cooling

47.38

59.38

1174 mm

1200 mm

T-Bar

46.92

58.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

One-Way

Alum

alum

Alum

Cooling

47.38

59.38

1174 mm

1200 mm

37HS4

T-Bar

46.92

58.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

2-Way

One-Way

Heating

Cooling

47.38

59.38

1174 mm

1200 mm

DIRECTOR DIFFUSER

T-Bar

46.92

58.92

Tegular T-Bar

Continuous T-Bar

Narrow T-Bar

Metric

Heating

Cooling

2-Way

47.38

59.38

1174 mm

1200 mm

DIRECTOR DIFFUSER

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The optimum air throw values given in the table are dis-

tances from the unit centerline to the outside wall or nearest

obstruction (wall, light ﬁxture or opposing air stream).

Throw for Standard Diffusers — Tables 24 and 25

provide the suggested minimum and maximum coverages

the Moduline® air terminals can handle in a typical instal-

lation while maintaining the desired room conditions.

Table 25 — Air Throw Data —

2-Way and 1-Way Director, 3-Slot Diffusers

Table 24 — Air Throw Data —

1-Way and 2-Way Blow, 2-Slot Diffusers

OPTIMUM AIR THROW (ft)

37HS1 UNIT

OPTIMUM AIR THROW (ft)

37HS1 UNIT

Heating

Cooling

AIRFLOW

(Cfm)

1-Way Blow

2-Way Blow

AIRFLOW

(Cfm)

1-Way Blow

2-Way Blow

Min

Max

Min

Max

Min

Max

Min

Max

2.0

4.0

7.0

9.0

2.0

3.0

3.5

4.0

4.5

5.0

6.0

7.0

5.0

6.0

2.0

4.0

7.0

9.0

2.0

3.0

3.5

4.0

4.5

5.0

6.0

7.0

5.0

6.0

7.5

12.0

15.0

18.0

20.0

22.0

24.0

7.5

8.0

9.0

10.0

11.0

12.0

9.0

7.5

12.0

15.0

18.0

20.0

22.0

24.0

7.5

10.5

11.5

13.0

15.0

8.0

9.0

10.0

11.0

12.0

9.0

10.5

11.5

13.0

15.0

100

110

100

110

OPTIMUM AIR THROW (ft)

1-Way Blow 2-Way Blow

37HS2 UNIT

AIRFLOW

(Cfm)

OPTIMUM AIR THROW (ft)

Heating Cooling

1-Way Blow 2-Way Blow

37HS2 UNIT

AIRFLOW

(Cfm)

Min

Max

Min

Max

100

120

140

160

180

200

220

2.0

4.0

7.0

9.0

2.0

3.0

3.5

4.0

4.5

5.0

6.0

7.0

5.0

6.0

Min

Max

Min

Max

7.5

12.0

15.0

18.0

20.0

22.0

24.0

7.5

100

120

140

160

180

200

220

2.0

4.0

7.0

9.0

2.0

3.0

3.5

4.0

4.5

5.0

6.0

7.0

5.0

6.0

8.0

9.0

10.0

11.0

12.0

9.0

10.5

11.5

13.0

15.0

7.5

12.0

15.0

18.0

20.0

22.0

24.0

7.5

8.0

9.0

10.0

11.0

12.0

9.0

10.5

11.5

13.0

15.0

OPTIMUM AIR THROW (ft)

1-Way Blow 2-Way Blow

37HS4 UNIT

AIRFLOW

(Cfm)

OPTIMUM AIR THROW (ft)

Heating Cooling

1-Way Blow 2-Way Blow

Min

Max

Min

Max

37HS4 UNIT

AIRFLOW

(Cfm)

160

200

250

300

350

400

440

8.5

10.0

11.0

12.0

14.0

15.0

17.0

16.0

20.0

21.0

22.0

23.0

25.0

29.0

5.0

6.0

7.0

10.0

13.0

17.0

19.0

21.0

24.0

7.0

Min

Max

Min

Max

8.0

9.0

10.0

13.0

160

200

250

300

350

400

440

8.5

10.0

11.0

12.0

14.0

15.0

17.0

16.0

20.0

21.0

22.0

23.0

25.0

29.0

5.0

6.0

7.0

10.0

13.0

17.0

19.0

21.0

24.0

7.0

8.0

9.0

10.0

13.0

NOTES:

1. Minimum air throw refers to the distance from the diffuser where the air ve-

locity is 150 fpm. In maximum air throw, this velocity has dropped to 50 fpm.

2. Data is based on an area with a 9-ft ceiling. For higher ceilings, values may

be reduced by one foot for each foot of height increase. For speciﬁc instal-

lations, minimum values can be reduced if properly qualiﬁed. Values are

dependent on cfm only and are not affected by duct pressure.

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Manufacturer reserves the right to discontinue, or change at any time, speciﬁcations or designs without notice and without incurring obligations.

Book 3

PC 201

Catalog No. 513-741

Printed in U.S.A.

Form 37HS-1XA

Pg 84

6-91

Replaces: New

Tab 6a

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