Carrier 42DH User manual

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53420022-01 Printed in U.S.A. Form 42DHV-2SI Pg 1 1-22 Replaces: 42DHV-1SI
Installation, Start-Up, and Service Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . 1
AHRI Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
C-ETL-US Listing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
PRE-INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . 3
Prepare Job Site for Unit Installation . . . . . . . . . . . . 3
Identify and Prepare Units . . . . . . . . . . . . . . . . . . . . . 3
Protect Units from Damage . . . . . . . . . . . . . . . . . . . . 3
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Step 1 — Place Unit In Position . . . . . . . . . . . . . . . . . 3
Step 2 — Install Mixing Box . . . . . . . . . . . . . . . . . . . . 7
Step 3 — Connect Cooling/Heating Piping . . . . . . . 10
Step 4 — Make Electrical Connections . . . . . . . . . . 19
Step 5 — Connect Ductwork . . . . . . . . . . . . . . . . . . 19
Step 6 — Make Final Preparations . . . . . . . . . . . . . 20
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Cooling/Heating System . . . . . . . . . . . . . . . . . . . . . . 20
Direct Expansion (DX) Systems . . . . . . . . . . . . . . . . 21
Air Balance System . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Motor/Blower Assembly . . . . . . . . . . . . . . . . . . . . . . 21
Electronically Commutated Motor (ECM) . . . . . . . . 21
Control Board Adjustment . . . . . . . . . . . . . . . . . . . . 21
Water Balancing System . . . . . . . . . . . . . . . . . . . . . 22
Water Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Electric Resistance Heater Assembly . . . . . . . . . . . 23
Cabinet/Control Box Maintenance Light . . . . . . . . . 24
Electrical Wiring and Controls . . . . . . . . . . . . . . . . . 24
Drain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Filters — Throwaway . . . . . . . . . . . . . . . . . . . . . . . . 24
Filters — Replacement and Installation . . . . . . . . . 24
APPENDIX A —TYPICAL WIRING DIAGRAM
EXAMPLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
START-UP CHECKLIST . . . . . . . . . . . . . . . . . . . . . CL-1
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service,
maintenance, or use can cause explosion, fire, electrical shock or
other conditions which may cause personal injury or property
damage. Consult a qualified installer, service agency, or your
distributor or branch for information or assistance. The qualified
installer or agency must use factory-authorized kits or accessories
when modifying this product. Refer to the individual instructions
packaged with the kits or accessories when installing.
Follow all safety codes. Wear safety glasses and work gloves. Use
quenching cloths for brazing operations and have a fire
extinguisher available. Read these instructions thoroughly and
follow all warnings or cautions attached to the unit. Consult local
building codes and appropriate national electrical codes (in USA,
ANSI/NFPA70, National Electrical Code (NEC); in Canada, CSA
C22.1) for special requirements.
It is important to recognize safety information. This is the safety-
alert symbol . When you see this symbol on the unit and in
instructions or manuals, be alert to the potential for personal
injury.
Understand the signal words DANGER, WARNING, CAUTION,
and NOTE. These words are used with the safety-alert symbol.
DANGER identifies the most serious hazards which will result in
severe personal injury or death. WARNING signifies hazards
which could result in personal injury or death. CAUTION is used
to identify unsafe practices, which may result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.
Equipment is initially protected under the manufacturer’s standard
warranty; however, this warranty is provided under the condition
that the steps outlined in this manual for initial inspection, proper
installation, commissioning, regular periodic maintenance, and
everyday operation of the equipment be followed in detail. This
manual should be fully reviewed and understood in advance of
initial installation, start-up, and any maintenance. Should any
questions arise, please contact your local Sales Representative or
the factory BEFORE proceeding.
WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause personal injury or
death.
Before performing service or maintenance operations on unit,
turn off main power switch to unit and install lock(s) and lock-
out tag(s). Unit may have more than one power switch.
CAUTION
CUT HAZARD
Sheet metal parts may have sharp edges or burrs. Use care and
wear appropriate protective clothing, safety glasses and gloves
when handling parts and servicing air conditioning equipment.
42DH, DV 06-30
Direct Drive Blower Fan Coils

2
Safety should always be first priority when handling, installing,
operating or servicing mechanical equipment. Always follow all
safety codes, procedures and protocols.
Consult applicable local building codes and National Electrical
Codes (NEC) for special requirements. See Fig. 1 for Proposition
65 warning label. Be alert to safety information: symbols, words
such as DANGER, WARNING and CAUTION.
Improper installation, adjustment, service, maintenance, or use
can cause explosion, fire, electrical shock, or other conditions,
which may result in personal injury or property damage. This
product must be installed only by personnel with the training, ex-
perience, skills, and applicable licensing that makes him/her “a
qualified professional HVACR (Heating, Ventilating, Air Condi-
tioning, and Refrigeration) installer.”
Fig. 1 — Proposition 65 Warning Label
AHRI Certification
Carrier’s Direct Drive Blower Coil units are certified in compli-
ance with Air-Conditioning, Heating, and Refrigeration Institute
(AHRI) industry standard AHRI-440 for room fan coil units.
C-ETL-US Listing
Carrier’s Direct Drive Series blower coil units are listed by
Intertek Testing Services (ITS). ITS’s C-ETL-US listing signifies
that Carrier’s blower coil units have been examined by ITS and
comply with the minimum requirements of U.S. and Canadian
national product safety standard, UL 1995/CSA C22.2 No. 236,
and that Carrier’s manufacturing site has been audited. ITS’s re-
examination service includes periodic visits to Carrier’s factory to
ensure continued compliance for all listed products.
Introduction
Carrier fan coil units represent a prudent investment offering trou-
ble free operation and long service with proper installation, opera-
tion, and regular maintenance. The equipment covered by this
manual is available with a variety of options and accessories.
Always consult the approved unit submittals, order acknowledg-
ment, and other manuals for specific details on unit options and
accessories. Always follow proper procedures related to safety,
handling, installation, operation, and servicing of mechanical
equipment as the manufacturer assumes no responsibility for per-
sonal injury or property damage resulting from improper or unsafe
practices during the handling, installation, service, or operation of
any equipment.
CAUTION
Disconnect all power prior to any installation or service (unit
may use more than one power source; ensure all are discon-
nected). Power to remote mounted control devices may not be
supplied by unit.
Install approved Lock-Out/Tag-Out protection devices on ALL
incoming power sources to equipment being installed or ser-
viced prior to beginning any work. Always verify all incoming
power sources are de-energized using an electrical multi-meter.
WARNING
NO ATTEMPT SHOULD BE MADE TO HANDLE, IN-
STALL, OR SERVICE ANY UNIT WITHOUT FOLLOW-
ING SAFE PRACTICES REGARDING MECHANICAL
EQUIPMENT.
Always use proper equipment support. Secure all pre-
installation supports.
CAUTION
Never wear bulky or loose fitting clothing when working on
any mechanical equipment. Gloves should always be worn for
protection against sharp sheet metal edges, heat, and other pos-
sible injuries. Safety glasses or goggles should always be
worn, especially when drilling, cutting, or working with refrig-
erants, lubricants or cleaning chemicals.
CAUTION
Always protect adjacent flammable material when welding or
soldering. Use a suitable heat shield material to contain sparks
or drops of solder. Have a fire extinguisher readily available.
CAUTION
Always protect chilled and hot water valve bodies, strainers,
ball valves, and other flow control related devices from heat
caused by soldering or brazing processes.
This product can expose you to chemicals
including Acrylamide, which is known to the
State of California to cause cancer and birth
defects or other reproductive harm.
For more information, go to
www.P65Warnings.ca.gov
WARNING
!
!
!
AVERTISSEMENT
ADVERTENCIA
Ce produit peut vous exposer à des produits
chimiques, y compris l’acrylamide, qui est
connu dans l’État de Californie pour causer
le cancer et des malformations congénitales
ou d’autres problèmes de reproduction. Pour
de plus amples informations, prière de
consulter www.P65Warnings.ca.gov
Este producto puede exponerlo a productos
químicos como la acrilamida, que en el
estado de California es causante de cáncer
y defects de nacimiento u otros daños
reproductivos. Para mayor información, visite
www.P65Warnings.ca.gov
343839-101 REV.A

3
PRE-INSTALLATION
Unpacking and Inspection
All units are carefully inspected at the factory throughout the
manufacturing process under a strict detailed quality assurance
program. All major components and sub-assemblies are carefully
tested for proper operation and verified for full compliance with
factory standards. Operational testing of some customer-furnished
components such as DDC (Direct-Digital Controls) controls,
pneumatic control valves and switches may be a possible
exception.
Each unit is carefully packaged for shipment to prevent damage
during normal transit and handling. Equipment should always be
stored in a dry and covered place, and in proper orientation
marked on the carton.
All shipments are made F.O.B. ex-factory and it is the responsibil-
ity of the receiving party to inspect the equipment upon arrival.
Any obvious damage to the packaging and/or its contents should
be recorded on the bill of lading and a claim filed with the freight
carrier.
After inspecting condition of packaging exterior, carefully remove
each unit from the carton and inspect for hidden damage. Any hid-
den damage or missing components should be recorded and
immediately reported to the carrier and a claim filed. In the event a
claim for shipping damage is filed, the unit, shipping carton, and
all packing must be retained for physical inspection by the freight
carrier. All equipment must be stored in the factory shipping car-
ton with internal packing in place until installation.
At time of receipt, equipment type and arrangement must be veri-
fied by review of order documents. Should any discrepancy be
found, the local Sales Representative must be notified immediate-
ly so that proper action may be taken.
Should any questions arise concerning field warranty repairs,
factory must be notified BEFORE any corrective action is taken.
When repairs or alterations can be accomplished locally, the
factory must be fully informed of the extent and expected cost
of repairs before work begins. When factory operations are re-
quired, the factory must be contacted for authorization to return
equipment and a Return Authorization Number will be issued.
Unauthorized return shipments of equipment and shipments not
marked with an authorization number will be refused. In addition,
any claims for unauthorized expenses will not be accepted by the
manufacturer.
Prepare Job Site for Unit Installation
To save time and to reduce the possibility of costly errors, set up a
complete sample installation in a typical room at the job site.
Check all the critical dimensions such as field piping, wiring, and
duct connection to ensure they agree with job requirements. Refer
to job drawings and product dimension drawings as required. In-
struct all trades in their part of the installation. Should any discrep-
ancies be discovered, contact your local representative before con-
tinuing with unit installations.
Identify and Prepare Units
For each unit, confirm incoming and control power requirements
match available power source. Refer to unit nameplate and wiring
diagram.
1. Review all tags on unit to determine if shipping screws are to
be removed. Remove screws as directed.
2. Rotate fan wheel by hand to ensure that fan is unrestricted
and can rotate freely. Inspect for shipping damage and fan
obstructions. Adjust blower wheel as required.
Protect Units from Damage
Care must be taken to assure that no force or pressure is applied to
the coil, piping or drain stub-outs during handling. The equipment
covered in this manual IS NOT suitable for outdoor installations.
The equipment is never to be stored or installed where it may be
subjected to a hostile environment such as rain, snow, or extreme
temperatures.
Before, during, and after installation, take specific caution to
prevent foreign material such as paint, plaster, and drywall dust
from being deposited in the drain pan, on the motor or blower
wheels and cooling/heating coils. Failure to do so may have seri-
ous adverse effects on unit operation, and in the case of motor
and blower assembly, may result in immediate or premature fail-
ure and voiding all manufacturers’ warranties. Some units and/or
job conditions may require some form of temporary covering
during construction. While the manufacturer is not involved in
the design and selection of support methods and components, it
shall be noted that unacceptable system operating characteristics
and/or performance may result from improper or inadequate unit
structural support. After mounting, the unit is then ready for the
various service connections such as water, drain and electrical.
Verify which proper type of services are actually provided to the
unit. On units requiring chilled water and/or hot water, verify
proper line size and water supply availability.
INSTALLATION
Step 1 — Place Unit In Position
Install mixing box when ordered with unit. Follow mixing box in-
stallation instructions outlined in the next section.
HORIZONTAL UNITS
The horizontal blower coil units have 5/8 in. knockouts in each
corner of the top and bottom panels for 1/2 in. all threaded rods
(not supplied with unit) to pass through. (See Fig. 2.) Always
support the unit at the base until mounting is complete.
VERTICAL UNITS
Vertical units need to be installed on a pad or on a base rail. The
height of the pad should be adequate to allow proper trapping for
condensate drain.
Sufficient clearance must be kept for service and maintenance.
Minimum recommended clearance for maintenance of the motor
and blower wheel is 29 in. on the access side of the unit. Filters
can be removed from both sides and the bottom of the filter frame
(horizontal unit) or top of the filter frame (vertical unit). If side ac-
cess to the filter is desired, the minimum clearance required is the
width of the filter rack plus 6 inches.
A minimum of 48 in. clearance is required between factory sup-
plied electric heater and any combustible materials. See Fig. 3 and
4 for additional clearances information. For drain pan or coil re-
moval, the recommended clearance should be no less than the
width of the unit plus connections.

4
Fig. 2 — Unit Installation - Threaded Rod Suspension
Fig. 3 — 42DH Horizontal Unit Installation - Recommended Clearances (Top View)
Isolators - 4 per unit
(Field furnished
and installed)
Washer And Double Nut (Field
Furnished and Installed)
5/8” Knockouts For
Suspension rods
(4 Places top and 4 places
Bottom of unit)
Threaded rod suspension (Field
Furnished and installed)
Trapeze -
Recommended on
Unit size 30
Minimum Recommended
Clearance
Minimum Recommended
Clearance
Electric Heat Controls
Airflow Airflow
Filter
Drain Pan
Electric Heat
Elements
29 In.
Minimum Recommended
Clearance
29 In.
29 In.
Fan Motor Piping Package
Fan

5
Fig. 4 — 42DV Vertical Unit Installation - Recommended Clearances (Top View)
29 In.
Minimum Recommened
Clearance
29 In.
Minimum Recommened
Clearance 29 In.
Minimum Recommened
Clearance
Filter
Piping Package
(*)
(*)
(*)
(*) For drain pan or coil removal, the recommended clearance should be no less than the width of the unit plus connections.

6
The unit must be mounted level. DO NOT mount the unit on a
slope. The drain pan has a built-in slope to ensure proper drainage.
Mounting the unit on a slope may result in improper drainage. For
threaded rod suspension see Fig. 5. Field-furnished and installed
accessories such as ductwork, mixing boxes, economizers, damp-
ers, etc. must be independently supported or suspended and must
not rely on the unit for support.
Fig. 5 — Threaded Rod Suspension Mounting Details
TOTAL WEIGHT UNIT CORRECTION FACTOR (LB)
See Fig. 6 and 7 for 8-row water-filled coils and double wall con-
struction (see Table 1). For a different number of rows, total unit
weight can be determined by:
1. Identify the size of unit and number of rows
2. From Fig. 6 or 7, identify the total weight of the unit
3. From Table 1, identify the correction factor and deduct this
factor from the total weight.
See Fig. 6 and 7 for operating weight information. Weight infor-
mation is based on 8-row water-filled coils and double wall cabi-
net construction. For a different coil and cabinet options, use the
weight correction factor table.
Table 1 — Total Unit Weight Adjustment
NOTES:
1. Unit weights (shown in pounds), ± 10%, are based on the largest
water-filled coil.
2. The operating weight information is based on 8-row water-filled
coils and double wall cabinet construction. For a different coil and
cabinet options, use the weight adjustment table.
Fig. 6 — 42DH Horizontal Unit —
Weight Distribution Calculations
OPTIONS 42DH, DV UNIT
06 08 10 12 16 20 22 30
4-Row Coil –21 –21 –28 –28 –39 –46 –46 –98
5-Row Coil –16 –16 –21 –21 –29 –35 –35 –74
6-Row Coil –11 –11 –14 –14 –20 –23 –23 –49
7-Row Coil –5 –5 –7 –7 –10 –12 –12 –25
Single Wall
Construction –31 –31 –40 –40 –47 –58 –58 –67
WASHER
DOUBLE NUTS
TRAPEZE
BOLT
42DH UNIT NO ELECTRIC HEAT (lb)
A B C D Total
06 42 46 36 47 171
08 41 47 38 45 171
10 51 53 49 63 217
12 50 52 51 64 217
16 65 70 64 75 274
20 78 90 77 95 340
22 83 108 80 99 367
30 103 113 97 117 430
42DH UNIT WITH ELECTRIC HEAT (lb)
A B C D Total
06 42 58 36 66 202
08 41 58 36 67 202
10 51 60 56 83 250
12 50 58 57 85 250
16 70 69 66 104 309
20 81 96 77 107 378
22 86 111 81 111 389
30 104 120 96 149 469
LH Coil
RH Coil

7
NOTES:
1. Unit weights (shown in pounds), ± 10 percent, are based on the
largest water-filled coil.
2. The operating weight information is based on 8-row water-filled
coils and double wall cabinet construction. For a different coil and
cabinet options, use the weight adjustment table (Table 1).
Fig. 7 — 42DV Vertical Unit —
Weight Distribution Calculations
Step 2 — Install Mixing Box
1. Mixing boxes are pre-assembled from the factory for ease of
installation. A linkage kit consisting of two crank arms,
2 swivels, and either a 25 in. (sizes 06-16) or a 34 in. (sizes
20-30) length of 5/16 in. rod is provided for field-installation
of an actuator. Mixing boxes are only compatible with side/
bottom (horizontal units) and side/top (vertical units)
access-style filter frames (non-magnetic latching doors). See
Fig. 14 for dimensional information.
2. Assemble the base rails (provided with mixing box. (See
Fig. 8.) All hardware required for assembly is included and
the base rails are letter coded for ease of assembly. (See
Fig. 9.)
Fig. 8 — Base Rails
Fig. 9 — Letter Coding on Base Rail Parts
PLACE UNIT ON THE BASE RAILS
42DH- Horizontal Units
Unit is mounted flush to the outer edge of the end base rail at the
aligning unit mounting holes. (See Fig. 10.) It may be necessary to
remove factory installed sheet metal screws to enable access to all
mounting holes and to ensure proper fit. Do not remove screws
unless necessary. Secure unit to base rail using No. 8 x 1/2 in. fas-
teners at the locations shown in Fig. 9 and 10. Use two fasteners
per side.
42DV UNIT NO ELECTRIC HEAT (lb)
A B C D Total
06 76 38 35 42 191
08 85 39 37 38 199
10 78 45 44 78 245
12 84 45 46 80 255
16 85 74 62 82 306
20 90 84 77 88 339
22 110 90 73 90 363
30 147 140 113 128 528
42DV UNIT WITH ELECTRIC HEAT (lb)
A B C D Total
06 85 40 44 49 218
08 94 48 44 47 234
10 86 58 55 84 283
12 97 62 58 92 309
16 105 79 70 92 346
20 111 88 81 99 379
22 133 88 92 99 412
30 160 140 131 137 568
CD
AB
B
DC
A
RH Coil
LH Coil

8
Fig. 10 — 42 DH Horizontal Units with
Mixing Box Option
42DV - Vertical Unit
Unit is mounted flush to the outer edge of the end base rail. Secure
base rail to unit with supplied No.12 x 3/4 in. sheet metal screws,
two per side at the aligning unit mounting holes indicated. (See
Fig. 11.)
Fig. 11 — 42DV Vertical Units with Mixing Box Option
PLACE MIXING BOX ASSEMBLY ONTO FRAME RAIL
42DH - Horizontal Units
For units with 1 in. and 2 in. filters, mount mixing box flush to the
outer edge of the end base rail, for units with 4 in. filters, the mix-
ing box will over-hang the base rail by 2 in. Slide duct flanges of
box over the flanges of the filter frame. It may be necessary to re-
move factory-installed sheet metal screws to enable access to all
mounting holes and to ensure proper fit. Do not remove screws
unless necessary. Secure base rail to mixing box with supplied
No. 8 x 1/2 in. sheet metal screws, two per side. (See Fig. 12.)
For bottom-entering configurations, length adjustments to the bot-
tom damper shaft may need to be completed prior to final
placement of the mixing box.
42DV - Vertical Units
Slide duct flanges of box over the flanges of the filter frame. It will
be necessary to remove factory installed sheet metal screws to en-
able access to some mounting holes and to ensure proper fit. Do
not remove screws unless necessary. For units with 4 in. filters, the
mixing box will over-hang the end base rail by 2 in. Secure side
base rail to mixing box with supplied No. 8 x 1/2 in. sheet metal
screws, two per side. (See Fig. 13.)
Fig. 12 — 42DH Horizontal Units with
Mixing Box Option
Fig. 13 — 42 DV Vertical Units with
Mixing Box Option
Detail A
See Detail A
See Detail A
Detail A
Detail A
SEE DETAIL A
42DH With 2" Filter Frame 42DH With 4" Filter Frame
See Detail B
See Detail A
Detail B
Detail A
See Detail A See Detail B
Detail B
42DV With 2" Filter Frame 42DV With 4" Filter Frame

9
3. Secure the mixing box to the filter frame using the supplied
sheet metal screws (No. 8 x 1/2 in. for horizontal units,
No. 8 x 1 in. for vertical units) at the mounting hole located at
the center of each duct flange. Seal the connection between
the mixing box and the return duct flange with appropriate
tape/sealant product. Be careful not to tape or seal the filter
access panel. (See Fig. 14.)
Fig. 14 — Optional Mixing Box
3(76)
A
C
2.4(61)
4(102)
H
2.4(61)
3(76)
1(25)
2(51)
2(51)
WB
Top Views
BTM/Rear Inlet - 42DH Top/Rear Inlet - 42DH
Top/Front Inlet - 42DV
W
4(102)
2.4(61)
C
1(25)
H
A
A
B
A
2.4(61)
DIMENSIONS in. (mm)
42DH, DV UNIT SIZE H W A B C
06 18.50 (470) 28 (711) 6 (711) 24 (610) 11 (279)
08 18.50 (470) 28 (711) 6 (711) 24 (610) 11 (279)
10 20.28 (514) 37 (940) 8 (940) 33 (828) 13 (330)
12 20.28 (514) 37 (940) 8 (940) 33 (828) 13 (330)
16 20.28 (514) 47 (1194) 8 (1194) 43 (1092) 13 (330)
20/22 22.75 (578) 48 (1219) 8 (1219) 44 (1118) 13 (330)
30 31.00 (787) 48 (1219) 10 (1219) 44 (1118) 15 (381)

10
INLET AND OUTLET DAMPERS INSTALLATION
1. Install actuator per manufacturer's instructions.
2. Adjust damper shafts outward to extend past any obstacles
that might cause interference. Do not adjust inward end of
shaft within a distance of 2 inches of bronze bushing.
3. Position inlet damper and outlet damper to coincide with cur-
rent or intended position of actuator arm, depending on actua-
tor's position (opened/closed). Note rotation direction of each
damper.
4. Install crank arms to each damper shaft approximately
parallel to each other while maintaining state/position of
dampers. (See Fig. 15.) Check for range of motion clearances
before tightening.
Fig. 15 — Install Crank
5. Install swivels to crank arms and hand tighten. (See Fig. 16.)
Fig. 16 — Install Swivels
6. Insert 5/16 in. damper rod through mounting hole of each
swivel. (See Fig. 17.) Position shaft to ensure there is not
interference at any point during travel. Tighten rod clamp of
swivel onto each damper rod.
Fig. 17 — Install Damper
7. Confirm correct operation of dampers. Adjust as needed.
Tighten remaining fasteners.
Step 3 — Connect Cooling/Heating Piping
Thoroughly review submittals and product literature detailing unit
operation, controls, and connections BEFORE beginning the
connection of the various cooling and/or heating mediums to the
unit. The supply and return connections are marked with a
“HS/CS” meaning Hot/Cold water Supply or inlet and “HR/CR”
meaning Hot/Cold water Return or outlet indicating fluid flow
direction into and from the coil. Refer to Fig. 18-25 and Tables 2
and 3 for details and Direct Expansion (DX) coils marking and
piping locations.
See Detail A
Detail A
CAUTION
Residue and loose particles resulting from manufacturing and
field piping techniques such as joint compounds, soldering
flux, and metal shavings may be present in the unit and the
piping system. This may cause damage to the unit. Ensure sys-
tem cleanliness when connecting to solar, domestic or potable
water systems.

11
Fig. 18 — 42DH Hydronic Coil Piping Connection Diagram, Left Hand Unit with Reheat Coil Shown
Fig. 19 — 42DV Hydronic Coil Piping Connection Diagram, Right Hand Unit with Reheat Coil Shown
COIL HEADER CONNECTION SIZE
Unit
Size
8 Row 6 Row 4 Row 2 Row HW 1 Row HW
Nom.
Size OD Nom.
Size OD Nom.
Size OD Nom.
Size OD Nom.
Size OD
CR - Cold Water Return
HR - Hot Water Return
CS - Cold Water Supply
HS - Hot Water Supply
RH - Right Hand
LH - Left Hand
NOTES:
1. Horizontal, left hand unit with re-heat coil shown.
2. Dimensions are in inches (mm).
0
0
2 (51)
B
C
6-7/8(175)
8-5/8(219)
E
D
1-5/8 (41)
A
2-11/16(68)
G
F
10-3/8(264)
06-12 1 1.125 3/4 0.875 3/4 0.875 1/2 0.625 1/2 0.625
16-22 1 1.125 1 1.125 1 1.125 11.125 1/2 0.625
30 1-1/2 1.625 1-1/2 1.625 1-1/2 1.625 1-1/2 1.625 1/2 1.625
HR
CR
CS
HS
Return Air
Drain
LH TELL-TALE RH TELL-TALE
LEGEND
2. Vertical, right hand unit with re-heat coil shown.
0
0
2 (51)
6-7/8(175)
8-5/8(219)
RH UNIT
1-5/8 (41)
2-11/16(68)
10-3/8(264)
LH UNIT
TELL-TALE
TELL-TALE
HR
CR
CS
HS
D
C
B
A
Drain
E
Return Air
G
F
COIL HEADER CONNECTION SIZE
Unit
Size
8 Row 6 Row 4 Row 2 Row HW 1 Row HW
Nom.
Size OD Nom.
Size OD Nom. Size OD Nom. Size OD Nom. Size OD
CR - Cold Water Return
HR - Hot Water Return
CS - C W S
HS - Hot Water Supply
RH - Right Hand
LH - Left Hand
1. Dimensions are in inches (mm).
06-12 1 1.125 3/4 0.875 3/4 0.875 1/2 0.625 1/2 0.625
16-22 1 1.125 1 1.125 1 1.125 1 1.125 1/2 0.625
30 1-1/2 1.625 1-1/2 1.625 1-1/2 1.625 1-1/2 1.625 1.625
1-1/2
NOTES:
LEGEND

12
Table 2 — Hydronic Coil Piping Connections
42DH/DV
UNIT SIZE
COIL ROWS A B C D E F G
Cool Heat
06/08
4
— —
6-1/8 12-3/4
———
5-15/161 3-1/2 15-1/2 7 7
2 3-13/16 15-13/16 7-9/16 7-9/16
6
—— ———
8-1/81 3-1/2 15-1/2 9-3/16 9-3/16
2 3-13/16 15-13/16 9-3/4 9-3/4
8 — — — — — 10-1/4
10/12
4
— —
7-3/4 14-3/8
———
5-15/161 5-1/8 17-1/8 7 7
2 5-7/16 17-7/16 7-9/16 7-9/16
6
—— ———
8-1/81 5-1/8 17-1/8 9-3/16 9-3/16
2 5-27/61 17-7/16 9-3/4 9-3/4
8 — — — — — 10-1/4
16
4
— — 7-3/4
15-5/8
———
5-15/161 LH 10-5/8 7-3/4 12 9-5/8 7
RH 13-3/8 9-5/8 7
2 12 7 16-3/8 13-5/8 10-3/8 7-9/16
6
— — 7-3/4
15-5/8
———
8-1/81 LH 10-5/8 7-3/4 12 11-13/16 9-3/16
RH 13-3/8 11-13/16 9-3/16
2 12 7 16-3/8 13-5/8 12-1/2 9-3/4
8 — — 9-1/2 15-5/8 — — — 10-1/4
20/22
4
— — 7-13/16
18-3/16
———
5-15/16
1LH 11-15/16 7-13/16 13-5/16 9-5/8 7RH 14-11/16
2 11-9/16 7-7/8 15-13/16 9-1/16 5
6
— — 7 13/16 — — —
8-1/8
1LH 11-15/16 7-13/16 13-5/16 11-3/16 9-3/16RH 14-11/16
2 11-9/16 7-7/8 15-13/16 11-1/4 7-1/8
8 — — 7-13/16 — — — 10-1/4
30
4
— —
5-15/16 26-5/16
— — — 5-15/16
1 7-1/16 25-13/16 9 7 4-7/8
2 10-5/16 23-13/16 9-1/8
6
— — — — — 8-1/8
1 7-1/16 25-13/16 11-1/8 9-1/8 7-1/16
2 10-5/16 23-13/16 11-5/16
8 — — — — — 10-1/4

13
Fig. 20 — 42DH DX Coil Piping Connection Diagram, Left Hand Unit with Preheat Coil Shown
Fig. 21 — 42DV DX Coil Piping Connection Diagram, Right Hand Unit with Preheat Coil Shown
NOTES:
1. Horizontal, left hand unit with pre-heat coil shown.
2. Dimensions are in inches (mm).
HR - Hot Water Return
HS - Hot Water Supply
LL - Liquid Line
SL - Suction Line
COIL HEADER CONNECTION SIZE (NOMINAL OD IN INCHES)
Unit
Size
LL SL 2 Row HW 1 Row HW
Nom.
Size OD Nom. Size OD Nom.
Size OD Nom. Size OD
0
0
2 (51)
B
D
6-7/8(175)
8-5/8(219)
A
G
H
E
1-5/8 (41)
F
C
06-12 0.3751/4 3/4 0.875 1/2 0.625 1/2 0.625
16-22 0.3751/4 1 1.125 1 1.125 1/2 0.625
30 0.6251/2 1- 1/2 1.625 1-1/2 1.625 1-1/2 1.625
LEGEND
HR
HS
SL
LL
Return Air
Drain
LH TELL-TALE RH TELL-TALE
NOTE: Vertical, right hand unit with pre-heat coil shown.
HR - Hot Water Return
HS - Hot Water Supply
LL - Liquid Line
SL - Suction Line
0
0
2(51)
B
6-7/8(175) 8-5/8(219)
A
G
DRAIN
RH UNIT
E
1-5/8(41)
F
C
LH UNIT
D
H
TELL-TALE TELL-TALE
COIL HEADER CONNECTION SIZE (NOMINAL OD IN INCHES)
Unit
Size
LL SL 2 Row HW 1 Row HW
Nom.
Size OD Nom. Size OD Nom. Size OD Nom. Size OD
06-12 0.3751/4 3/4 0.875 1/2 0.625 1/2 0.625
16-22 0.3751/4 1 1.125 1 1.125 1/2 0.625
30 0.6251/4 1-1/2 1.625 1-1/2 1.625 1-1/2 1.625
LEGEND
HR
HS
SL
LL
Return Air

14
Table 3 — DX Coil Piping Connection
42DH/DV
UNIT
SIZE
COIL ROWS
A B C D E F G H
WATER
PRE-HEAT DX Only
06/08
—4
4-3/4 5-1/2
— —
12 1/2
2-3/4 — —
6
14
6 18
3-3/4 2-5/8 2-5/8
6
244-7/8 3-1/4 3-1/4
6
10/12
—4
6-1/2 7-1/8
— —
12 1/2
2-3/4 — —
6
14
5-1/8 17-1/8
3-3/4 2-5/8 2-5/8
6
244-7/8 3-1/4 3-1/4
6
16
—4
6-1/2
7-1/8
— —
12 1/2
2-3/4 — —
6
145-1/8 17-1/8 3-3/4 2-5/8 2-5/8
6
246-3/8 10 13-5/8 6-6/8 4-1/8 2-5/8
6
20/22
—4
6-1/2 7-1/8
— —
12 1/2
2-3/4 — —
6
145-1/4 19-3/4 3-3/4 2-5/8 2-5/8
6
246-3/4 7-1/4 11-5/8 15-7/8 6-6/8 4-1/4 2-5/8
6
30
—44-5/8 5-3/8 — —
12 1/2
2-3/4 — —
6
14
4-7/8
6 12-1/8 25-7/8 6-1/8
4-1/2 2-5/8
6
245-3/8 10-3/8 23-7/8 6-3/8
6

15
Fig. 22 — 42DH Unit Submittal Drawing
NOTES:
1. Right hand unit shown; left hand unit opposite.
2. All dimensions are ± 1/4 in.
3. Product specifications are subject to changes without notice.
4. Dimensions are in inches (mm).
5. Allow adequate spacing or maneuverability around unit to allow service through recommended access area.
6. C dimension is measured from coil side of unit.
7. Mixing box option will vary return duct dimensions, refer to mixing box drawing.
8. Auxiliary control box required with 3-speed EC motors and/or cabinet lighting option; not required with low voltage (0-10v) controls.
UNIT
SIZE
FAN
SIZE DEPTH WIDTH HEIGHT SUPPLY DUCT RETURN DUCT MOUNTING HOLES
AUX.
CTRL.
BOX M
A B C D E F G J K L
06 9 x 6 36 28 19-3/4 8-7/8 10-7/8 13-3/4 2-1/4 24-1/4 14 2-3/4 27-1/4 35-1/4 5-3/4 2
08 9 x 6 36 28 19-3/4 8-7/8 10-7/8 13-3/4 2-1/4 24-1/4 14 2-3/4 27-1/4 35-1/4 5-3/4 2
10 9 x 6 37-1/2 37 21-1/2 10-1/4 10-7/8 14-1/2 2-1/4 33-1/4 15-3/4 2-7/8 36-1/4 37 5 2
12 9 x 6 37-1/2 37 21-1/2 10-1/4 10-7/8 14-1/2 2-1/4 33-1/4 15-3/4 2-7/8 36-1/4 37 5 2
16 10 x 7 37-3/4 47 21-1/2 13 12 18-3/8 2-1/4 43-7/8 15-3/4 2-7/8 46-1/4 37 1-1/4 1-1/2
20/22 11 x 10 40-1/4 48 24 16-1/4 13 17-1/4 2-1/4 44-1/4 18 2-7/8 47-1/4 39-1/2 2-3/8 2
30 12 x 12 40-1/4 48 32-1/4 16-1/4 14 16 7-1/8 44-1/4 26-1/2 1-1/4 47-1/4 39-1/2 3-3/4 2
NOTE: Drawing is not to scale and is provided
for reference only. Dimensions may vary
with options ordered.

16
Fig. 23 — 42DH Unit with Mixing Box Submittal Drawing
NOTES:
1. Right hand unit shown; left hand unit opposite.
2. All dimensions are ± 1/4 in.
3. Product specifications are subject to changes without notice.
4. Dimensions are in inches (mm).
5. Allow adequate spacing or maneuverability around unit to allow service through recommended access area.
6. C dimension is measured from coil side of unit.
7. Mixing box option will vary return duct dimensions, refer to mixing box drawing.
8. Mixing box option includes: a) knockdown base rails for field assembly; b) pre-assembled mixing box.
9. Linkage kit supplied with Mixing Box is provided for field installation of actuator.
10. Add 2 in. if using a prefilter or 4 in. filter.
11. Auxiliary control box required with 3-speed EC motors and/or cabinet lighting option; not required with low voltage (0-10v) controls.
UNIT
SIZE
FAN
SIZE DEPTH UNIT DEPTH WIDTH HEIGHT SUPPLY DUCT RETURN DUCT
MIX
BOX MOUNTING
HOLES
AUX.
CTRL.
BOX M
A B C D E F G H J K L
06 9 x 6 51-5/8 36 28 22-3/4 8-7/8 10-7/8 13-3/4 2-1/4 24 6 12-1/2 11 27-1/4 35-1/4 5-3/4 2
08 9 x 6 51-5/8 36 28 22-3/4 8-7/8 10-7/8 13-3/4 2-1/4 24 6 12-1/2 11 27-1/4 35-1/4 5-3/4 2
10 9 x 6 55-1/8 37-1/2 37 24-1/2 10-1/4 10-7/8 14-1/2 2-1/4 33 8 14-1/4 13 36-1/4 37 5 2
12 9 x 6 55-1/8 37-1/2 37 24-1/2 10-1/4 10-7/8 14-1/2 2-1/4 33 8 14-1/4 13 36-1/4 37 5 2
16 10 x 7 55-3/8 37-3/4 47 24-1/2 13 12 18-3/8 2-1/4 43 8 14-1/4 13 46-1/4 37 1-1/4 2
20/22 11 x 10 57-3/4 40-1/4 48 27 16-1/4 13 17-1/4 2-1/4 44 8 16-3/4 13 47-1/4 39-1/2 2-3/8 2
30 12 x 12 59-3/4 40-1/4 48 35-1/4 16-1/4 14 16 7-1/8 44 10 15 15 47-1/4 39-1/2 3-3/4 2
NOTE: Drawing is not to scale and is provided
for reference only. Dimensions may vary
with options ordered.

17
Fig. 24 — 42DV Unit Submittal Drawing
NOTES:
1. Right hand unit shown; left hand unit opposite.
2. All dimensions are ± 1/4 in.
3. Product specifications are subject to changes without notice.
4. Dimensions are in inches (mm).
5. Allow adequate spacing or maneuverability around unit to allow service through recommended access area.
6. C dimension is measured from coil side of unit.
7. Mixing box option will vary return duct dimensions, refer to mixing box drawing.
UNIT
SIZE
FAN
SIZE DEPTH WIDTH HEIGHT SUPPLY DUCT FLANGE RETURN DUCT
FLANGE
AUX.
CTRL.
BOX
UNIT SIDE TO
DUCT
FLANGE
UNIT
BOTTOM TO
DUCT
FLANGE
A B C E F L M N
06 9 x 6 20 28 36-1/2 8-7/8 10-7/8 15-1/8 24-1/4 14 4-1/2 1-7/8 2-7/8
08 9 x 6 20 28 36-1/2 8-7/8 10-7/8 15-1/8 24-1/4 14 4-1/2 1-7/8 2-7/8
10 9 x 6 22 37 39-3/8 10-1/4 10-7/8 21-1/2 33-1/4 15-3/4 0 1-7/8 2-7/8
12 9 x 6 22 37 39-3/8 10-1/4 10-7/8 21-1/2 33-1/4 15-3/4 0 1-7/8 2-7/8
16 10 x 7 22 47 39-3/8 13 12 16-5/8 43-7/8 15-3/4 3 1-5/8 2-7/8
20/22 11 x 10 24 48 45-1/8 16-1/4 13 17-1/8 44-1/4 18 2-1/2 1-7/8 3-1/8
30 12 x 12 28 48 54-1/4 16-1/4 14 16 44-1/4 26-1/2 3-5/8 1-7/8 2-3/4

18
Fig. 25 — 42DV Unit with Mixing Box Submittal Drawing
NOTES:
1. Right hand unit shown; left hand unit opposite.
2. All dimensions are ± 1/4 in.
3. Product specifications are subject to changes without notice.
4. Dimensions are in inches (mm).
5. Allow adequate spacing or maneuverability around unit to allow service through recommended access area.
6. C dimension is measured from coil side of unit.
7. Mixing box option will vary return duct dimensions, refer to mixing box drawing.
8. Mixing box option includes: a) knockdown base rails which are letter-coded for field assembly, all assembly hardware included; b) pre-assem-
bled mixing box.
9. Linkage kit supplied with Mixing Box is provided for field installation of actuator. Kit consists of 2 crank arms, 2 swivels, and either a 25 in.
(sizes 06-16) or 34 in.(sizes 20-30) length of 5/16 in. rod.
10. Add 2 in. if using a prefilter or 4 in. filter.
UNIT
SIZE
FAN
SIZE DEPTH UNIT DEPTH WIDTH HEIGHT SUPPLY DUCT FLANGES
RETURN
DUCT
FLANGES
MIX
BOX
AUX.
CTRL.
BOX
UNIT SIDE TO
DUCT FLANGE
UNIT BOTTOM TO
DUCT FLANGE
A B C E F H L M N
06 9 x 6 35-1/2 20 28 36-1/2 8-7/8 10-7/8 15-1/8 24 6 11 4-1/2 1-7/8 2-7/8
08 9 x 6 35-1/2 20 28 36-1/2 8-7/8 10-7/8 15-1/8 24 6 11 4-1/2 1 2-7/8
10 9 x 6 39-1/2 22 37 39-3/8 10-1/4 10-7/8 21-1/2 33 8 13 0 1-7/8 2-7/8
12 9 x 6 39-1/2 22 37 39-3/8 10-1/4 10-7/8 21-1/2 33 8 13 0 1-7/8 2-7/8
16 10 x 7 39-1/2 22 47 39-3/8 13 12 16-5/8 43 8 13 3 1-5/8 2-7/8
20/22 11 x 10 41-1/2 24 48 45-1/8 16-1/4 13 17-1/8 44 8 13 2-1/2 1-7/8 3-1/8
30 12 x 12 47-1/2 28 48 54-1/4 16-1/4 14 16 44 10 15 3-5/8 1-7/8 2-7/8

19
LEAK TESTING
After securing the connections, test the system for any leaks.
Always test hydronic systems with water as some components are
not designed to be inert gas pressurized.
Field pressure testing for leaks should not exceed 300 psi for
hydronic coil and valve package components. Consult factory if
higher limits are required.
REFRIGERANT COIL TESTING
Test refrigerant systems with dry nitrogen rather than air to pre-
vent the introduction of moisture into the system. In the event that
leaking or defective components are discovered, notify the Sales
Representative BEFORE any repairs are attempted. All leaks must
be repaired before proceeding with the installation. In DX
systems, adequate freeze protection should be field-installed. Ex-
ternal equalizer should be installed by others.
PIPING INSULATION
After system integrity has been established, insulate the piping in
accordance with the project specifications. This is the responsibili-
ty of the installing or insulation contractor.
CONDENSATE DRAIN
Any fan coil unit with a drain pan is recommended to be equipped
with a drain trap to provide condensate drainage and prevent prop-
erty damage.
The drain U-trap should be deep enough to offset maximum unit
static pressure difference as shown at Fig. 26, to prevent conden-
sate flowing back to drain pan.
Fig. 26 — Condensate Drain U-Trap
CONDENSATE FLOAT SWITCH
The condensate float switch is used to detect clogged or restricted
condensate pan drains. The condensate switch uses a Normally
Closed contact to allow the system control power to pass through
the switch energizing the water valves and fans allowing normal
operation. When an overflow condition is detected by the switch,
it opens the NC contacts and de-energizes the water valves and
fans.
Step 4 — Make Electrical Connections
The unit serial plate lists the unit electrical characteristics includ-
ing the required supply voltage, fan and heater amperage and re-
quired circuit ampacity. (See Fig. 27.) The unit wiring diagram
displays all unit and field wiring. Every project is different and
each unit on a project may be different, the installer must be famil-
iar with the wiring diagram and serial plate on the unit BEFORE
beginning any wiring.
Ensure all field electrical connections are in accordance with unit
wiring diagram and all applicable national and local code. The
type and size of all wiring and other electrical components includ-
ing circuit breakers, disconnect switches, etc. shall be determined
by the individual job requirements. Verify conductor size is suit-
able for the distance to the equipment connection and will support
the equipment electrical load. All installations including field
wiring shall be made in compliance with all governing codes and
ordinances. Compliance with all codes is the responsibility of the
installing contractor.
All components furnished for field installation by either the facto-
ry or the controls contractor shall be located and checked for prop-
er function and compatibility. Inspect all internal components for
shipping damage. Inspect all electrical connections within the unit
control box and accessories and tighten if necessary.
NOTE: All field wiring must be in accordance with governing
codes and ordinances. Any modification of unit wiring without
factory authorization will invalidate all factory warranties and
nullify any agency listings. The manufacturer assumes no respon-
sibility for any damages and/or injuries resulting from improper
field installation and/or wiring.
Fig. 27 — Serial Plate Example
CABINET/CONTROL BOX MAINTENANCE LIGHT
Optional Service Light provides a source of illumination in the
main unit cabinet and the control box during routine maintenance
and troubleshooting in the dark ceiling spaces. Light turns "ON"
when access panel or control box door is open, but unit is not pow-
ered. (See Fig. 28.)
Step 5 — Connect Ductwork
All ductwork shall be installed in accordance with the project
plans and specifications. See Fig. 22-25 for supply and return duct
flanges location and dimensions.
NOTE: When installing units that attach to branch duct piping, use
industry approved duct standards and configuration such as those
published by Air Conditioning Contractors of America (ACCA)
or American Society of Heating, Refrigeration and Air Condition-
ing Engineers (ASHRAE). The standards provide necessary infor-
mation on sizing, layout and installing supply and return air duct
systems.
Flexible duct connections should be used on all air handling
equipment. All ductwork and insulation shall be installed to allow
proper access to all components for service and repair such as fil-
ters, motor/blower assemblies, etc.
CAUTION
Protect all water coils from freezing after initial filling with
water. Even if the system is drained, unit coils may still hold
enough water to cause damage when exposed to temperatures
below freezing.
Drain Pan
Safety Margin
TSP
TSP
To Drain
Max Water Coil Leaving Air or Max Motor AMB:
Max Fuse or Max Circ Breaker (HACR Type NEC):
Unit Intended for Indoor Use Only & Suited For 0.00 Clearance From Combustible Surfaces
-
25A - SCCR: 5KA
Unit Serial No:
Model No:
42DHA20 776004-60-1
ELECTRICAL ENV/PERF
Motor(s):
Motor VPH:
Motor FLA:
Heater AMPS:
QTY of Motor(s):
Motor HP:
Min Circ Amps:
Heater VPH:
E020-71537402
277/1/60
5.10A
18.1A
5.0 kW
1
1 HP
29.0A
277/1/60
Max ESP:
Max Inlet Water Temp:
Coil Test:
High Side Coil Design:
Refrigerant Type:
1.65
300 PSIG
-
-
Max Outlet Air Temp:
Max Hot Water or Steam:
ARI Model:
Low Side Coil Design:
-
42DHA20
-
190F
2 PSIG
Heater Kw:
Motor Current: 5.10A
Manufactured in the USA

20
Fig. 28 — Control Box Layout
Step 6 — Make Final Preparations
1. Power unit(s) off (open unit electrical disconnect) and install
lockout tags on all power supplies to the unit.
2. Install field-supplied thermostats and perform all other final
wiring needed. Ensure all electrical connections are secure.
3. Perform final visual inspection. All equipment, ductwork,
and piping should be inspected to verify all systems are com-
plete and properly installed and mounted, and that no debris
or foreign articles are left in the unit(s). Clean dirt, dust, and
other construction debris from unit interior. Assess fan wheel
and housing and clean if necessary.
4. Verify drain line is properly and securely positioned and that
the line is clear. Pour water into drain to verify operation.
5. Rotate fan wheel by hand to be sure it is free and does not rub
housing.
6. Install the filter into the filter frame. If field-supplied filters
are used, verify filter size (see Table 4).
Table 4 — Filter Sizes
7. Ensure all panels and filters are installed before checking fan
operation. Turn on power to the unit.
8. Inspect the fan and motor operation.
START-UP
Before beginning any start-up operation, the start-up personnel
shall familiarize themselves with the unit, options and accessories,
and control sequence to understand the proper system operation.
All personnel shall have a good working knowledge of general
start-up procedures and have the appropriate start-up and
balancing guides available for consultation.
The building must be completely finished including doors,
windows, and insulation. All internal walls and doors should be
installed. In some cases, the interior decorations and furniture may
influence overall system performance. The entire building should
be as complete as possible before beginning any system balancing.
Cooling/Heating System
Prior to the water system start-up and balancing, flush the
chilled/hot water systems to clean out dirt and debris which may
have collected in the piping during construction. During this pro-
cedure, all unit service valves must be in the closed position to
prevent foreign matter from entering the unit and clogging the
valves and metering devices. Strainers shall be installed in the
piping mains to prevent such material from entering units during
normal operation.
During system filling, air venting from the unit is accomplished
by the use of the standard, manual air vent fitting, or the option-
al, automatic air vent fitting installed on the coil. (See Fig. 29).
Manual air vents are basic Schrader valves that could be
accessed from the coil side of the unit and are located between
the coil header and end sheet. To vent the air from the coil, de-
press the valve until the air has vented the coil. When water be-
gins to escape through the valve, release the valve.
Automatic air vents may be unscrewed one turn counterclockwise
to speed initial venting, but should be screwed in for automatic
venting after start-up operations.
Motor
Control
Board
Equipment
Ground
Terminal
Terminal Strip
Wiring Diagram
(inside the door)
Serial Plate
Wrapper
Contactors
Transformer
Electric Heater
Limit Switch Knob Heater Fuses
Auxillary Control Box
(supplied when ordered
with 3-speed controls
and/or service light)
Service Light
Strip
Battery
Charger
Service Light
Battery
Door Switch
Bonded
Ground
24v Control
Fuse
Disconnect Switch
NOTE: Above is the example of Control box for Size 20 unit with electric heat, disconnect switch and service light.
42DH/DV
UNIT SIZE
FILTER
QUANTITY
NOMINAL FILTER SIZES
in. (mm)
06 1 16-1/2 x 24 (419 x 610)
08 1 16-1/2 x 24 (419 x 610)
10 1 18-1/4 x 33 (464 x 838)
12 1 18-1/4 x 33 (464 x 838)
16 2 18-1/4 x 21-1/2 (464 x 546)
20/22 2 20-1/2 x 22 (521 x 559)
30 2 29 x 22 (737 x 559)