Carrier MODULINE 37HS User manual

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53370001-01 Printed in U.S.A. Form 37HS-10SI Pg 1 8-18 Replaces: 37HS-1SI
Installation Instructions
CONTENTS
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . 1
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Unit Identification . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Installation Precautions . . . . . . . . . . . . . . . . . . . . . 3
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Unit/Ceiling Coordination . . . . . . . . . . . . . . . . . . . . 8
Unit-to-Unit Connections . . . . . . . . . . . . . . . . . . . . 8
Unit Suspension . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
•T-BAR SUPPORT
• OTHER SUPPORTS
Unit Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
• T-BAR CEILING
• TEGULAR CEILING
• NON-ACCESSIBLE CEILINGS
Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
• GENERAL
• CONTROL ARRANGEMENTS
• OPERATING SEQUENCES
• CONTROL INSTALLATION
• AIRFLOW ADJUSTMENT
• FUNCTIONAL CHECKOUT
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Principles of Operation . . . . . . . . . . . . . . . . . . . . . 30
• GENERAL
• CONSTANT VOLUME OPERATION
• VARIABLE AIR VOLUME OPERATION
Preliminary System Check . . . . . . . . . . . . . . . . . . 30
Initial Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
• GENERAL CHECKOUT
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Gaining Access to Control Area . . . . . . . . . . . . . 30
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . 31
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Checking for Obstruction . . . . . . . . . . . . . . . . . . . 31
Checking for Leaks . . . . . . . . . . . . . . . . . . . . . . . . 31
To Check Duct Pressure . . . . . . . . . . . . . . . . . . . . 31
SAFETY CONSIDERATIONS
Air-handling equipment will provide safe and reliable service
when operated within design specifications. The equipment
should be operated and serviced only by authorized personnel
who have a thorough knowledge of system operation, safety
devices and emergency procedures.
When installing this unit, observe precautions in the literature,
tags and labels attached to the equipment, and any other safety
precautions that may apply.
See Fig. 1 for Proposition 65 warning label.
Fig. 1 — Proposition 65 Warning Label
INTRODUCTION
Moduline® units are integral diffuser air terminals. They are
available with various control devices for constant volume
and variable volume heating and cooling applications.
All units consist of a plenum, valve assembly and diffuser. A
typical unit is shown in Fig. 2. The plenum is thermally and
acoustically insulated and contains a distribution baffle to
provide well-distributed flow to the valve assembly. Figure 3
shows a cross section of a typical 37HS unit.
The valve assembly includes the bellows, which is inflated in
proportion to the duct pressure to regulate airflow to the
space. The bellows is constructed of durable polyurethane.
The assembly is connected at either end to 1∕4-in. OD control
tubing.
The diffuser assembly is available in a 2-slot, one-way or 2-
way blow configuration. A 3-slot director diffuser is available
for use in cooling/heating applications.
The standard diffuser assembly is not removable. Control ac-
cess is made through a ceiling opening (e.g., a removable
ceiling tile) or nearby light fixture. The 37HS Moduline ter-
minal is also available with a removable diffuser for installa-
tion in non-accessible ceilings.
Fig. 2 — Typical 37HS Moduline Air Terminal
!WARNING: Cancer - www.P65Warnings.ca.gov
VALVE
ASSEMBLY
PLENUM
CENTER
DIFFUSER
SIDE DIFFUSERS
37HS
Moduline®Air Terminals

2
Fig. 3 — Typical 37HS Moduline Unit Cross Section
INSTALLATION
Unit Identification
Units are factory-shipped one per carton. Compare unit
nameplate with model number nomenclature shown in Fig. 4
to be sure correct unit has been received.
Installation Precautions
When installing units, make sure that construction debris
does not enter unit or ductwork. Do not remove protective
tape from diffuser until installation is complete.
Do not operate the central station air-handling fan without the
final filter in place. Accumulated dust and debris can smudge
ceilings and damage unit controls.
Fig. 4 — Model Number Nomenclature for Unit Identification
CAUTION
To avoid damage to bottom units, do not stack units
more than 8 high. Make sure that arrows on cartons
point up.
DIGIT 1 2 3 4 5 6 7 8 9 10 11 12 13
MODELNO. 37HS2-3862LNC
37HS — System-Powered
Terminal Unit
Unit Size — Airflow (Nominal Cfm)
1 — 100
2 — 200
4 — 400
-— Not used
Plenum Size
1—5“x7“
2—7“x7“
3—9“x9“
4—11“x11“
5—13“x13“
X — Special (Quote Control)
Inlet Diameter
4—4“Round
6—6“Round
8—8“Round
0—10“Round
2—12“Round
X — Special (Quote Control)
Outlet Diameter
N — None
4—4“Round
6—6“Round
8—8“Round
0—10“Round
2—12“Round
X — Special (Quote Control)
Packaging
C — Carton
Order Program
N — Standard
E — E-Z Sell
Diffuser Length
A — 22.92“(unit size 1 only)
B—23“(unit size 1 only)
C — 23.38“(unit size 1 only
D — 23.99“(unit size 1 only)
H — 46.92“
J—47“(standard)
L — 47.38“
M—48“
Q — 58.92“(unit sizes 2 and 4 only)
R—59“(unit sizes 2 and 4 only)
S — 59.38“(unit sizes 2 and 4 only)
T—60
“(unit sizes 2 and 4 only)
X — Special
Discharge and Slots
1 — One-Way Blow, 2-Slot
2 — 2-Way Blow, 2-Slot
3 — 3-Slot Director Diffuser
7 — Removable Diffuser
(2-Way Blow, 2-Slot, Aluminum)
EXAMPLE: Model No. 37HS2-3862LNC describes a 37HS2 unit with a 9-in. x 9-in. plenum,
inlet diameter of 8 in., outlet diameter of 6 in. and a 2-way blow, 2-slot, 47.38-in.
long diffuser. The unit is standard order and is shipped in a single carton.
K — 1200 mm
G — 1174 mm

3
General
The Moduline® 37HS units are designed for installation in
standard, narrow and Tegular T-bar ceilings, and for continu-
ous run, concealed spine or plaster ceilings. They can also be
provided for custom ceilings.
All 37HS Moduline units can be installed as single units or in
an air series. Layout guidelines for proper installations can be
found in the 37HS Application Data book.
Unit dimensions are shown in Fig. 5-7. Dimensions for dif-
fuser options are shown in Fig. 8 and 9. See Fig. 10 for acces-
sory return-air diffuser dimensions and Fig. 11 for accessory
dummy diffuser dimensions. Table 1 lists installation acces-
sories for 37HS Moduline units.
Fig. 5 — 37HS1 Unit Dimensions
NOTE: Dimensions are in inches.
37HS1 Plenum Dimensions
PLENUM SIZE CDEGHJ
B1B2
7 5 - - 4 - 8 20.94
7 7 22.94 4 6 8 9 -
7 7 22.94 6 6 9 9 -
9 9 22.94 6 8 9 10 -
9 9 22.94 8 8 10 10 -
11 11 22.94 8 10 10 11 -
11 11 22.94 10 10 11 11 -
37HS1 Standard Diffuser Lengths Available (in inches)
A122.92 23.00 23.38 23.99
F12.60 2.60 2.60 2.60
A246.92 47.00 47.38 48.00
F219.56 19.56 19.56 19.56

4
Fig. 6 — 37HS2 Unit Dimensions
Fig. 7 — 37HS4 Unit Dimensions
NOTE: Dimensions are in inches.
37HS2 Plenum Dimensions
PLENUM SIZE (sq)
BCDEG H J
7 - - 6 - 9 39.25
7 41.25 6 6 9 9 -
9 41.25 6 8 9 10 -
9 41.25 8 8 10 10 -
11 41.25 8 10 10 11 -
11 41.25 10 10 11 11 -
37HS2 Standard Diffuser Lengths Available (in inches)
A46.92 47.00 47.38 48.00 58.92 59.00 59.38 60.00
F1.25 1.25 1.25 1.25 7.25 7.25 7.25 7.25
NOTE: Dimensions are in inches.
37HS4 Plenum Dimensions
PLENUM SIZE (sq)
BCDEG H J
9 - - 8 - 11.50 39.25
9 41.25 8 8 11.50 11.50 -
11 41.25 8 10 11.50 12.50 -
11 41.25 10 10 12.50 12.50 -
13 41.25 10 12 12.50 13.50 -
13 41.25 12 12 13.50 13.50 -
37HS4 Standard Diffuser Lengths Available (in inches)
A46.92 47.00 47.23 47.38 48.00 58.92 59.00 59.38
F1.25 1.25 1.25 1.25 1.25 7.25 7.25 7.25

5
Fig. 8 — Optional Diffusers for 37HS1, HS2
Fig. 9 — Optional Diffusers for 37HS4
Dimensions are in inches.
REMOVABLE DIFFUSER (STEEL) REMOVABLE DIFFUSER (ALUMINUM)
EXTRUDED ALUMINUM
2-WAY BLOW
EXTRUDED ALUMINUM
ONE-WAY BLOW
EXTRUDED ALUMINUM
3-SLOT
37HS1 (100 cfm) Diffuser Options
CEILING T-BAR STYLE AND WIDTH DIFFUSER LENGTH (in.)
STANDARD 15/16 T-BAR 23.00
47.00
TEGULAR 15/16 T-BAR 22.92
46.92
CONTINUOUS RUN 15/16 T-BAR 24.00
48.00
NARROW 9/16 T-BAR 23.38
47.38
37HS2 (200 cfm) Diffuser Options
CEILING T-BAR STYLE AND WIDTH DIFFUSER LENGTH (in.)
STANDARD 15/16 T-BAR 47.00
59.00
TEGULAR 15/16 T-BAR 46.92
58.92
CONTINUOUS RUN 15/16 T-BAR 48.00
60.00
NARROW 9/16 T-BAR 47.38
59.38
EXTRUDED ALUMINUM
2-WAY BLOW
EXTRUDED ALUMINUM
ONE-WAY BLOW
EXTRUDED ALUMINUM
3-SLOT
REMOVABLE DIFFUSER (STEEL) REMOVABLE DIFFUSER (ALUMINUM)
Dimensions are in inches.
37HS4 (400 cfm) Diffuser Options
CEILING T-BAR STYLE AND WIDTH DIFFUSER LENGTH (in.)
STANDARD 15/16 T-BAR 47.00
59.00
TEGULAR 15/16 T-BAR 46.92
58.92
CONTINUOUS RUN 15/16 T-BAR 48.00
60.00
NARROW 9/16 T-BAR 47.38
59.38

6
Fig. 10 — Accessory Return-Air Diffusers
Fig. 11 — Accessory Dummy Diffusers
EXTRUDED ALUMINUM
2-WAY BLOW
EXTRUDED ALUMINUM
ONE-WAY BLOW
EXTRUDED ALUMINUM
3-SLOT
Available Lengths (in.) of Accessory
Return-Air Diffusers
37HS1 37HS2 37HS4
23.00 47.00 47.00
47.00 47.38 47.38
- 59.00 59.00
NOTES:
1. Dummy diffusers for other lengths can be field-cut from standard sizes.
2. Dummy diffusers are suspended in T-bar ceilings using one-piece
mountings brackets.
A (in.)
47.00
48.00
59.00
60.00
37HS1,2
37HS4

7
Table 1 — Installation Accessories for 37HS Units
ADAPTER CAP, Qty 12
Adapter Package No.
For 6-in. round adapter 37AH900102
For 8-in. round adapter 37AH900042
For 10-in. round adapter 37AH900212
DIFFUSER BAFFLE, Qty 50
Used On Length (in.) Package No.
37HS1, HS2 8 37AH900072
37HS4 81/237CN900622
T-BAR MOUNTING BRACKETS,
Qty 24 (with wedges)
T-Bar
Tegular
Used on 37HS1, HS2 Package No.
2-Slot T-Bar 37CM900002
2-Slot Tegular
1/2-in. 37CM900032
7/16-in. 37CM900042
3/8-in. 37CM900052
5/16-in. 37CM900062
1/4-in. 37CM900072
3-Slot T-Bar 37CM900012
3-Slot Tegular
1/2-in. 37CM900082
7/16-in. 37CM900092
3/8-in. 37CM900102
5/16-in. 37CM900112
1/4-in. 37CM900122
Used on 37HS4 Package No.
2-Slot T-Bar 37CN900002
2-Slot Tegular
1/2-in. 37CN900042
7/16-in. 37CN900052
3/8-in. 37CN900062
5/16-in. 37CN900072
1/4-in. 37CN900082
3-Slot T-Bar 37CN900012
3-Slot Tegular
1/2-in. 37CN900092
7/16-in. 37CN900102
3/8-in. 37CN900112
5/16-in. 37CN900122
1/4-in. 37CN900132
MOUNTING BRACKETS FOR RETURN AIR AND DUMMY DIFFUSERS
UNIT PACKAGE NO. QTY
One-Piece Mounting Bracket
37HS1, HS2 2-Slot T-Bar 35BD900002 50
37HS1, HS2 3-Slot T-Bar 37CM900022 50
37HS4 2-Slot T-Bar 37CN900022 50
2-Piece-Mounting Bracket
37HS4 3-Slot T-Bar 37CN900012 24
FILLER TRIM PIECE, Qty 100
Used On Diffuser Package No.
37HS1, HS2 2-Slot, One-Way or 2-Way Blow 37CM900712
3-Slot 37CM900722
37HS4 2-Slot, One-Way or 2-Way Blow 37CM900722
3-Slot 37CN900642
NOTE: For use with wire-hung units and continuous run units in accessible ceilings. Do not use removable diffusers.

8
Unit/Ceiling Coordination
Set up a ceiling mock-up to familiarize all trades with their
functions during installation. Coordinate unit installation with
ceiling construction. This is particularly important in custom
installations with special mounting considerations.
Unit-to-Unit Connections
Use field-fabricated round duct or flex duct as required.
Unit Suspension
T-BAR SUPPORT
Units are held in place by 2 accessory T-bar mounting brack-
ets and are locked in place with factory-supplied wedges.
The mounting brackets fit over the main T-bars, allowing the
T-bars to carry unit weight. Install T-bar support wires close
to each end of T-bar mounting brackets. Make sure that only
wire-hung, main T-bars are used to support unit weight.
Figure 12 shows a 37HS unit suspended in a T-bar ceiling.
OTHER SUPPORTS
When installed in non-accessible ceilings, or in accessible
ceilings that require wire-hung units, the 37HS is held in
place by field-installed accessory hanger mounting brackets.
The brackets are wire-hung from the building structure and
are adjustable for proper unit alignment. Figure 13 shows a
37HS unit wire-hung from the building structure.
NOTE: When units are wire-hung in accessible ceilings, T-bar
mounting brackets can be used for ceiling alignment.
Fig. 12 — 37HS Unit Installed in a T-Bar Ceiling
END TRIM, Qty 50
T-Bar
Tegular
Used on 37HS1, HS2 Color Package No.
2-Slot T-Bar* White 37CM900132
2-Slot Tegular†
White 37CM900252
Black 37CM900352
Black and White 37CM900452
3-Slot T-Bar* White 37CM900142
3-Slot Tegular†
White 37CM900302
Black 37CM900402
Black and White 37CM900502
Used on 37HS4 Color Package No.
2-Slot T-Bar* White 37CN900142
2-Slot Tegular†
White 37CN900162
Black 37CN900262
Black and White 37CN900362
3-Slot T-Bar* White 37CN900152
3-Slot Tegular†
White 37CN900212
Black 37CN900312
Black and White 37CN900412
*Used in continuous run units in non-accessible ceilings (to fill space between units) and in concealed spline and plaster ceilings to finish off end of
diffuser.
†Used to finish the exposed end of diffuser.
ALIGNMENT CHANNEL
Used On Diffuser Package No.
37HS1, 37HS2 2-Slot, One-Way or 2-Way Blow,
and 3-Slot 37CM900752
37HS4 2-Slot, One-Way or 2-Way Blow,
and 3-Slot 37CN900652
NOTE: For use with wire-hung units and continuous run units in accessible ceilings. Do not use with removable diffusers.
TUBING PACKAGES
Usage Type Package No.
Wall Thermostat and
Interconnecting Units
1/4-in. OD FR (Fire Retardant
Tubing) 35BB900172 (250 ft roll)
Miscellaneous Connections 3/16-in. ID EPDM (Synthetic
Rubber Tubing) 37AE900592 (100 ft roll)
HANGER MOUNTING BRACKET
Package No. 37AE901032
Table 1 — Installation Accessories for 37HS Units (cont)

9
Fig. 13 — 37HS Unit Wire-Hung in a T-Bar Ceiling
Unit Installation
T-BAR CEILING
NOTE: Moduline® systems are normally designed with multiple
unit and control arrangements within a single system.
Proper system operation is dependent on careful adherence to
the specified job layout. Become familiar with and check the
various control arrangements required on a particular job be-
fore installing the terminals. Additional information on unit
types and control combinations is given in Control Arrange-
ments section on page 16.
1. Move units in cartons to installation area.
2. Remove units from cartons and discard packaging mate-
rial. Do not remove protective tape from diffuser. When
handling units, take care not to damage diffusers and
adapters.
3. Arrange units on floor per design layout, diffuser side up.
Check unit identification.
4. Wherever a unit is to be installed directly to another unit,
attach field-supplied connecting duct (flex or metal duct)
to one unit with screws or other mechanical fasteners
before installing the next unit. Seal joint.
5. Install controls in designated units as indicated in job
layout and as described in Control Installation section on
page 23, then proceed to Step 6.
6. Install T-bar mounting bracket in each end of unit as
shown in Fig. 14. Insert bracket in unit side diffusers and
push evenly until bracket seats against diffuser end.
7. Raise unit above ceiling and lower into position. Engage
T-bar mounting bracket tabs securely over main T-bars.
Do not rest unit diffusers on T-bar flanges. Install 2 lock-
ing wedges on each bracket between bracket and T-bar.
See Fig. 15. It may be desirable to crimp the bracket
wedge assembly with pliers to ensure tightness.
8. On single-unit applications, make supply-air connection
directly to adapter on end of unit.
9. If other units are to be connected to the first unit, install
T-bar mounting brackets on each end of the adjoining
units.
10. Raise each unit above ceiling and lower into position.
Engage mounting brackets over main T-bar. Reposition
locking wedges at mounting bracket so that they also
secure the mounting bracket of the adjoining unit.
11. Connect interconnecting duct between units, and seal.
Fig. 14 — Installing T-Bar Mounting Bracket
Fig. 15 — T-Bar Mounting Details
Installation of Return-Air Diffusers and Dummy Diffusers
Install one-piece mounting brackets onto diffuser ends using
screws provided. See Fig. 16. (For 37HS 3-slot director dif-
fuser, use 2-piece mounting bracket.) Raise unit to ceiling and
set in position with the tabs of the mounting bracket placed
securely over the T-bar upright.
Wire-Hung Installations (With T-Bar Mounting Brackets
Used for Alignment)
Install accessory hanger mounting brackets, 2 on each end of
the 37HS unit, and attach eyebolts as illustrated in Fig. 17. In-
stall T-bar mounting brackets in end of diffuser; then raise
units above ceiling and lower to previously installed hanger
wires. Be sure to engage tabs of T-bar mounting brackets over
T-bar. Adjust eyebolts to permit T-bar mounting brackets to
just sit on the ceiling T-bars. All unit weight must be support-
ed by the hanger wires on the unit.
Continuous Run Installations
Continuous run units have diffuser lengths equal to the full
length of the ceiling module; for 2, 4 and 5-ft modules, the
diffusers measure 24, 48 and 60-in., respectively.
Units are wire-hung as described in Wire-Hung Installations
section, except that no T-bar mounting brackets are used, not
even for alignment. Instead, accessory alignment channels
are used in the side diffusers of adjoining units to ensure
alignment of the diffuser assemblies from unit to unit. As
shown in Fig. 18 and 19, the channel is inserted first into a
T- BAR SUPPORT WIRE
(MAIN T- BAR MEMBER)
WEDGE
MOUNT BRACKET
WEDGE

10
unit that has already been installed, and then into the next unit
as the unit is being positioned in the ceiling structure. After
alignment channel is installed, filler trim piece can be
snapped into place.
Fig. 16 — One-Piece Mounting Bracket Installed on
Diffuser End
Fig. 17 — Installed Hanger Mounting Brackets
Fig. 18 — Inserting Alignment Channel into Unit
Fig. 19 — Installed Alignment Channel and
Filler Trim Piece
FILLER
TRIM PIECE
ALIGNMENT
CHANNEL

11
TEGULAR CEILING
A tegular (recessed T-bar) ceiling is constructed the same as a
standard T-bar type ceiling, except that each lay-in ceiling
panel is rabbeted. This means that the panel is notched to fit
over the T-bar. When installed in the T-bar frame, the panel
hangs below the grid. From inside the room, the ceiling effect
is that of a recessed grid. This variation of the standard T-bar
concept provides all the T-bar ceiling advantages (simplicity,
ease of installation, low first-cost and accessibility) with an
architecturally more attractive appearance.
Tegular (recessed T-bar) ceilings are provided by many ceil-
ing manufacturers under various trade names, but are basical-
ly of the same design. All models of Moduline® 37HS air ter-
minals are adaptable to the recessed T-bar ceiling. They are
applied in a manner similar to the standard T-bar ceiling.
The system usually consists of a 15∕16-in. grid member sus-
pended by wires to form a 4 ft x 4 ft module. These support
wires should be located very near to the terminals and lights
to avoid twisting of the grid. The module is further subdivid-
ed using cross T-bar members creating sub-modules. Each
sub-module may be filled with a light fixture or a tile.
The 37HS Moduline terminal may be used in the center of a
2 ft x 4 ft ceiling tile, or to replace a recessed T-bar member.
In either case, the tile is cut and rests directly on the unit side
diffuser, so that the unit is flush with the ceiling tile plane.
The recessed T-bar may be painted (usually black with white
tiles) to create an interesting grid pattern. The 37HS unit cen-
ter diffuser (when installed on the grid line) may be painted to
match.
The depth of the notch or rabbet (dimension from grid face to
tile face) varies from manufacturer to manufacturer but is
normally between 3∕16-in. and 5∕8-inches. The mounting pack-
age for recessed grid (tegular) installation differs from the
standard T-bar mounting package. The proper mounting
package for the Moduline 37HS air terminal must drop the
unit to the level of the tile face (below the T-bar grid face).
The mounting bracket slides into the ends of the diffuser and
engages the T-bar. Wedges are used to secure the units in
place. It may be desirable to crimp the bracket wedge assem-
bly with pliers to ensure tightness and unit alignment.
Figure 20 shows a Moduline 37HS air terminal unit in a typi-
cal 2 ft x 4 ft recessed T-bar ceiling. For this application, the
overall diffuser length of the unit is 46.92 inches. For 5 ft x 5
ft ceiling module, the diffuser length used is 58.92 inches.
This shorter diffuser is used to allow room for 2 end trim
pieces which finish the exposed end of the installed unit. This
length is also used for dummy diffusers and return-air diffus-
ers when used in recessed T-bar ceilings. The end trim piece
is installed between the unit diffuser ends and the T-bar and is
held in place by bending the end piece over the unit mounting
bracket as shown in Fig. 20.
Fig. 20 — Typical Tegular (Recessed T-Bar) Ceiling Installation Using 37HS Air Terminals

12
NON-ACCESSIBLE CEILINGS
Non-accessible ceilings include plaster and concealed spline
ceilings. These applications require the 37HS unit equipped
with a removable diffuser assembly. Removal of the diffuser
assembly allows access to the unit controls and tubing con-
nections. To remove diffuser assembly, loosen 3 screws by in-
serting an allen wrench through diffuser slot as shown in
Fig. 21. After diffuser is removed, disconnect aspirator tube
and the tube connected to thermostat. When using removable
diffuser with standard controls, longer tubing must be in-
stalled between thermostat and volume controller and be-
tween aspirator and unit end. This will enable connections to
be retained when diffuser assembly is dropped below the ceil-
ing line. Disconnect aspirator and thermostat connections be-
fore completely removing diffuser. When diffuser assembly
is reinstalled, the connections can be made below the ceiling
line and the assembly completed with the capscrews.
Plaster Ceiling
Obtain plaster frames field fabricated to the dimensions
shown in Fig. 22. Install accessory hanger mounting brackets
on the unit. The diffuser protective tape should be left in
place during the installation.
Unit installation details may differ due to the many plastering
methods used. The actual installation procedure is left to the
discretion of the individual plasterer. One typical method,
shown in Fig. 21, shows 2 Model Moduline® 37HS air termi-
nals installed. Wire hangers with eyebolts for leveling and
supporting the terminals are shown at the plenum ends. The
units are directly coupled for a feed-thru application, with an
end trim piece used between units. The end trim piece may be
fastened to either unit. One unit is a control unit and the other
a slave unit. A 12-in. crossover tube is used to make the con-
trol connection. The end trim strip is added to the diffusers of
the end units before the actual installation. Then the units are
suspended below the finished ceiling level. A field-supplied
plaster frame is installed completely around the unit. A wire
mesh, which is supported by wires from the ceiling cross
members, is then attached to the plaster frame. These cross
members have been wired to main runners which have been
suspended from the building structure. The plaster scratch
coat is then troweled beyond the edge of the side diffuser.
When the plaster has set, the unit is then raised to the proper
level. This is accomplished either through hand holes cut into
the plaster, through a nearby light fixture, or by removing the
diffuser assembly. The final surface finish is now applied
with diffuser assembly lowered 3∕8-in. from unit.
NOTE: The entire diffuser assembly must be removable from
the unit for access to the unit and controls.
Fig. 21 — Installation Details, Moduline®Air Terminals in a Plaster Ceiling

13
Fig. 22 — Plaster Ceiling Opening for
37HS Removable Diffuser Unit
When this final finish has dried, the protective tape on the dif-
fuser is removed and the diffuser raised tight to the ceiling.
Figure 23 shows Moduline® units installed in a plaster ceiling
along with standard 2 ft x 4 ft light fixtures. Also shown are 2
cross-sectional detail views of the diffuser. Section A-A
shows the installed unit and the plaster interface.
Section B-B is a view of the plaster frame resting on the dif-
fuser end trim strip. The installed Moduline® air terminal pro-
vides an excellent, secure installation.
The 37HS Moduline matching dummy and return-air diffus-
ers may also be independently suspended when applied in a
plaster ceiling.
Concealed Spline Ceiling
In a concealed spline ceiling, the tiles butt together to provide
the roomside appearance of a smooth, nondirectional surface.
Each tile (usually 12-in. square) is grooved on 4 sides so that
it locks into a spline which is fastened to the main runners by
a secondary runner (typically Z-shaped). The main runners,
usually located 4 ft on centers, are suspended from the build-
ing structure by wires. This system also accommodates a 2 ft
x 4 ft standard light fixture. Because the tiles must be re-
moved with a special knife-like tool to provide access to the
ceiling cavity, this ceiling also offers the kind of security re-
quired for such installations as classrooms and other institu-
tional applications.
The 37HS Moduline® ceiling air terminals easily integrate
into concealed spline ceiling systems without compromising
any features. Moduline units equipped with removable diffus-
er assemblies (as shown in Fig. 21) allow access to unit con-
trols and tubing connections. The units are suspended by
wires from the building structure independent of the suspend-
ed ceiling. Hanger brackets with eyebolts, helpful in leveling
the suspended units, are also available.
When the terminal is installed, the tile will rest on the unit
side diffuser. For T-bar ceilings, diffusers with lengths of 23-
in., 47-in., or 59-in. can be used. For continuous run units,
diffusers with lengths of 24-in., 48-in., or 60-in. should be
used. Return-air diffusers, dummy diffusers and other acces-
sory hardware are available to suit a variety of application re-
quirements. The return-air and dummy diffusers are similar in
shape and width so that when matched with a Moduline air
terminal system, a ceiling pattern is retained or created. A
typical Moduline concealed spline installation is shown in
Fig. 24 and 25.
Plaster Ceiling Openings
UNIT DIFFUSER DIMENSIONS (in.)
AB
37HS1
2-Way 35/16 24
One-Way
3-Slot 4 48
37HS2
2-Way 35/16 48
One-Way
3-Slot 4 60
37HS4
2-Way 448
One-Way
3-Slot 33/460

14
Fig. 23 — 37HS Moduline®Units Installed in a Plaster Ceiling
Fig. 24 — Typical Concealed Spline Ceiling Using 37HS Air Terminals (Details)

15
Fig. 25 — Typical Concealed Spline Ceiling Using 37HS Air Terminals

16
Controls
GENERAL
System-powered or duct pressure controls used with Mod-
uline® terminals provide both volume and temperature con-
trol without the need for separate pneumatic or electric ener-
gy. The plenum pressure supplies the power required by the
control devices. Figure 26 shows the variable air volume sys-
tem-powered controls installed on the unit. The standard
37HS control arrangement is shown in Fig. 27.
NOTE: Although 37A, 37C and 37HS controls operate on simi-
lar principles, the pressure relationships between the 3 models of
units are different. Therefore, 37HS units cannot be operated
with 37A or 37C controls.
CONTROL ARRANGEMENTS
Table 2 shows the many control combinations available for
37HS Moduline air terminals and the control packages re-
quired for each set of functions. Figure 28 shows the installa-
tion of 3 control arrangements.
Fig. 26 — Variable Air Volume Controls
Installed on Unit
Fig. 27 — Standard 37HS Control Arrangement.
AIR FILTER
ASPIRATOR
THERMOSTAT
SPRING
CLIP VOLUME CONTROLLER

17
Fig. 28 — Control Arrangements - Master Units with Slaves
SINGLE MASTER UNIT INSTALLATION
MASTER UNIT WITH ONE SLAVE
MASTER UNIT WITH 3 SLAVES

18
OPERATING SEQUENCES
System powered control for the Moduline® terminal is shown
schematically in Fig. 29.
System Powered Cooling
A high-pressure signal and a low-pressure signal, measured
across the control unit distribution baffle, are transmitted
through the unit control block to the control air filter and to
the volume controller. The difference between the high and
low pressure is an indication of the unit airflow. The control
air filter, besides preventing dirt from entering the control
system, also acts as a manifold to connect the volume control-
ler to the unit.
The high-pressure and low-pressure signals act on dia-
phragms in the volume controller to position a seat relative to
a bleed nozzle. The relationship of the seat to the bleed nozzle
determines the air pressure transmitted back through the con-
trol filter to the unit bellows, which inflates to a position nec-
essary to provide the airflow as preset on the volume control-
ler. A change in input pressures caused by changes in duct
pressures will cause the seat to be repositioned, relative to the
bleed nozzle, and change the output pressure to the bellows to
maintain the unit airflow. The airflow is pre-set using the
maximum airflow adjusting lever.
The thermostat, wall-mounted or diffuser-mounted, is con-
nected to the volume controller to provide a means of varying
the airflow delivery as room temperature varies from the ther-
mostat set point. As room temperature cools to the cooling
thermostat set point, another bleed orifice in the thermostat
opens and bleeds control air from the volume controller low
side. This causes the volume controller seat to move toward
the bleed nozzle, increasing the bellows output pressure, thus
closing the unit.
A minimum airflow can be set on the volume controller to
prevent the unit from closing completely. The minimum air-
flow adjustment restricts the volume controller seat from
closing the bleed nozzle, thus preventing the unit from fully
closing. A hood airflow measurement is required to set mini-
mum airflow.
System Powered Cooling With Warm-Up
The cooling thermostat (diffuser-mounted or wall-mounted)
is a direct acting thermostat. With the space temperature at a
nighttime condition below the set point, the thermostat port is
open, reducing the pressure on the upper diaphragm (A) and
causing the element assembly (B) to rise. This closes the
bleed port (C), which diverts high pressure to the bellows, re-
ducing the unit flow. In warm-up, hot air flows over the im-
mersion warm-up switch installed in unit plenum. The switch
closes, raising the low-side pressure on the volume controller
diaphragm and moving the element away from the bleed noz-
zle. This reduces the bellows pressure and permits warm duct
air to flow to the space.
System Powered Heating and Cooling
The 37HS can provide heating as well as cooling with the ad-
dition of a changeover switch installed in the unit plenum and
a wall heating/cooling thermostat. A separate amplifier is not
required.
With cold air below 65°F in the duct, the changeover is con-
nected to the cooling side of the thermostat, and the bellows
is bled at the volume controller according to the pilot pressure
from the thermostat. Hot air in the plenum shifts the connec-
tion to the heating side of the thermostat.
Fig. 29 — 37HS Control Schematic

19
Table 2 — 37HS Control Combinations
NO. FUNCTION MODEL
CONTROL
PACKAGES
REQUIRE
CONNECTION ARRANGEMENT
1
SYSTEM POWERED
CONSTANT VOLUME
COOLING
37HS1 37HS900003
37HS2 37HS900003
37HS4 37HS900003
2
SYSTEM POWERED
VARIABLE VOLUME
COOLING
DIFFUSER
THERMOSTAT
37HS1 37HS900001
37HS2 37HS900002
37HS4 37HS900004
3
SYSTEM POWERED
VARIABLE VOLUME
COOLING
WALL THERMOSTAT
37HS1 37HS900003
37CM901012
37HS2 37HS900003
37CM901012
37HS4 37HS900003
37CM901012

20
4
SYSTEM POWERED
VARIABLE VOLUME
COOLING
SYSTEM POWERED
WARM-UP
WALL THERMOSTAT*
37HS1
37HS900003
37CM900152
37CM901012
37HS2
37HS900003
37CM900152
37CM901012
37HS4
37HS900003
37CM900152
37CM901012
5
SYSTEM POWERED
VARIABLE VOLUME
HEATING AND COOLING
SYSTEM POWERED
CHANGEOVER
WALL THERMOSTAT
37HS1
37HS900003
37CM900192
37CM901992
37HS2
37HS900003
37CM900192
37CM901992
37HS4
37HS900003
37CM900192
37CM901992
6
SYSTEM POWERED
VARIABLE VOLUME
COOLING
ELECTRIC WARM-UP
WALL THERMOSTAT*
37HS1
37HS900003
37CM900792†
37CM901012
37HS2
37HS900003
37CM900792†
37CM901012
37HS4
37HS900003
37CM900792†
37CM901012
LEGEND
DA — Direct Acting
NC — Normally Closed
NO — Normally Open
RA — Reverse Acting
*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. (See Table 3, pages 26-27.)
**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.
††For night set back heating, a field-supplied dual set point DA thermostat must be substituted for thermostat packages shown. For VAV Moduline®
cooling/separate system heating, a field-supplied dual set point DA/RA thermostat must be substituted for thermostat packages shown.
Table 2 — 37HS Control Combinations (cont)
NO. FUNCTION MODEL
CONTROL
PACKAGES
REQUIRE
CONNECTION ARRANGEMENT