Mars Comfort-Aire Century Compact HEH Series Owner's manual

97B0130N01
Issue Date: July 8, 2021
Installation, Operation &
Maintenance
Compact (HEH/HEV) Series
HEH-HEV 024-60
60Hz - HFC-410A

Installation, Operation, Maintenance
2
Installation, Operation & Maintenance - HEH/HEV Compact Series
Table of Contents
Model Nomenclature 3
General Information 4
Unit Physical Data 6
Horizontal Installation 7
Field Conversion of Air Discharge 9
Horizontal Installation 10
Vertical Installation 11
Piping Installation 13
Variable Flow Heat Pump Applications Overview 14
Water-Loop Heat Pump Applications 17
Ground-Loop Heat Pump Applications 18
Ground-Loop and Ground Water Heat
Pump Applications 19
Ground-Water Heat Pump Applications 20
Water Quality Standards 22
Electrical - Line Voltage 23
Electrical Data 25
Electrical - Power & Low Voltage Wiring 26
Electrical - Low Voltage Wiring 27
Electrical - Low Voltage Wiring for non-Variable Flow
Units Using External Motorized Water Valve 28
Electrical - Thermostat Wiring 29
Blower Performance Data 30
ECM Blower Control 31
HE Series Wiring Diagram Matrix 32
DXM2 Controls 33
DXM2 Layout and Connections 36
DXM2 Controls 37
Unit Starting and Operating Conditions 39
Piping System Cleaning and Flushing 40
Unit and System Checkout 41
Unit Start-Up Procedure 42
Unit Operating Conditions 43
Preventive Maintenance 46
Troubleshooting 47
DXM2 Process Flow Chart 49
Functional Troubleshooting 50
Performance Troubleshooting 52
Start-Up Log Sheet 54
Functional Troubleshooting 55
Warranty 59
Revision History 60

Installation, Operation, Maintenance 3
Installation, Operation & Maintenance - HEH/HEV Compact Series
Model Nomenclature
Note: Above model nomenclature is a general reference. Consult individual engineering
guides for detailed information.
H E H D0 3 6 D1 0 0 A S P
1 32 4 5 67
8
9 10 11 12 13 14
H = HORIZONTAL
MODELTYPE
HE = HEAT CONTROLLER RESIDENTIAL 410A
CONFIGURATION
V = VERTICAL
UNIT SIZE
024, 030, 036, 042, 048, 060
REVISION LEVEL
D = Current Revision
VOLTAGE
CONTROLS
RETURN AIR OPTIONS
S = LEFTRETURN w/ 1” Merv 8 Pleated Filter and Frame
T = RIGHTRETURN w/ 1” Merv 8 Pleated Filter and Frame
SUPPLY AIR OPTIONS
P = BACK DISCHARGE, HORIZONTAL ONLY
W = STRAIGHT DISCHARGE, HORIZONTAL ONLY
K =TOP DISCHARGE, VERTICALONLY
CABINET INSULATION
0 = RESIDENTIAL
1 = 208-230/60/1
D = DXM 2
In Position 11 and 12, only the following combinations are available:
Without HWGWith HWG Description
2A
2LInternal Flow Controller with Copper Water Coil
5A
5LMotorized Modulating Valve with Copper Water Coil
6J
6MMotorized Modulating Valve with Cupro-Nickel Water Coil
OA
OLNo vFlow™ with Copper Water Coil
OJ
OMNo vFlow™ with Cupro-Nickel Water Coil
WATER CIRCUIT OPTIONS
0 = NONE
2 = Internal Flow Controller w/High Head Pump
B = Closed loop w/Internal Flow Controller w/o Check Valve
5 = Motorized Valve (Modulating). Closed Loop Application,
Low System Pressure Drop.
6 = Motorized Valve (Modulating). Open Loop Application,
High System Pressure Drop.
HEAT EXCHANGER OPTIONS
A= Copper Water Coil w/Tin Plated Air Coil
J = Cupro-Nickel Water Coil w/Tin Plated Air Coil
L= Copper Water Coil w/Tin Plated Air Coil and HWG w/Internal Pump
M= Cupro-Nickel Water Coil w/Tin Plated Air Coil and HWG w/Internal Pump

Installation, Operation, Maintenance
4
Installation, Operation & Maintenance - HEH/HEV Compact Series
General Information
WARNING! To avoid the release of refrigerant into the
atmosphere, the refrigerant circuit of this unit must be
serviced only by technicians who meet local, state, and
federal prociency requirements.
CAUTION! To avoid equipment damage, DO NOT use
these units as a source of heating or cooling during the
construction process. The mechanical components and lters
can quickly become clogged with construction dirt and debris,
which may cause system damage and void product warranty.
⚠ WARNING! ⚠
WARNING! All refrigerant discharged from this unit must
be recovered WITHOUT EXCEPTION. Technicians must
follow industry accepted guidelines and all local, state, and
federal statutes for the recovery and disposal of refrigerants.
If a compressor is removed from this unit, refrigerant circuit
oil will remain in the compressor. To avoid leakage of
compressor oil, refrigerant lines of the compressor must be
sealed after it is removed.
⚠ WARNING! ⚠
⚠ CAUTION! ⚠
Safety
Warnings, cautions, and notices appear throughout this
manual. Read these items carefully before attempting any
installation, service, or troubleshooting of the equipment.
DANGER: Indicates an immediate hazardous situation,
which if not avoided will result in death or serious injury.
DANGER labels on unit access panels must be observed.
WARNING: Indicates a potentially hazardous situation,
which if not avoided could result in death or serious injury.
CAUTION: Indicates a potentially hazardous situation or
an unsafe practice, which if not avoided could result in
minor or moderate injury or product or property damage.
NOTICE: Notication of installation, operation, or
maintenance information, which is important, but which is
not hazard-related.
Inspection - Upon receipt of the equipment, carefully
check the shipment against the bill of lading. Make sure
all units have been received. Inspect the packaging of
each unit, and inspect each unit for damage. Ensure that
the carrier makes proper notation of any shortages or
damage on all copies of the freight bill and completes a
common carrier inspection report. Concealed damage
not discovered during unloading must be reported to the
carrier within 15 days of receipt of shipment. If not led
within 15 days, the freight company can deny the claim
without recourse.
Note: It is the responsibility of the purchaser to le all
necessary claims with the carrier. Notify your equipment
supplier of all damage within fteen (15) days of
shipment.
Storage - Equipment should be stored in its original
packaging in a clean, dry area. Store units in an upright
position at all times. Stack units a maximum of 3 units
high.
Unit Protection - Cover units on the job site with
either the original packaging or an equivalent protective
covering. Cap the open ends of pipes stored on the
job site. In areas where painting, plastering, and/or
spraying has not been completed, all due precautions
must be taken to avoid physical damage to the units and
contamination by foreign material. Physical damage and
contamination may prevent proper start-up and may
result in costly equipment clean-up.
⚠ WARNING! ⚠
WARNING! The installation of water-source heat pumps and
all associated components, parts, and accessories which
make up the installation shall be in accordance with the
regulations of ALL authorities having jurisdiction and MUST
conform to all applicable codes. It is the responsibility of
the installing contractor to determine and comply with ALL
applicable codes and regulations.

Installation, Operation, Maintenance 5
Installation, Operation & Maintenance - HEH/HEV Compact Series
General Information, Cont’d.
CAUTION! All three phase scroll compressors must have
direction of rotation veried at start-up. Verication is
achieved by checking compressor Amp draw. Amp draw
will be substantially lower compared to nameplate values.
Additionally, reverse rotation results in an elevated sound
level compared to correct rotation. Reverse rotation will result
in compressor internal overload trip within several minutes.
Verify compressor type before proceeding.
CAUTION! DO NOT store or install units in corrosive
environments or in locations subject to temperature or
humidity extremes (e.g., attics, garages, rooftops, etc.).
Corrosive conditions and high temperature or humidity can
signicantly reduce performance, reliability, and service life.
Always move and store units in an upright position. Tilting
units on their sides will cause equipment damage.
⚠ CAUTION! ⚠
⚠ CAUTION! ⚠
⚠ CAUTION! ⚠
CAUTION! CUT HAZARD - Failure to follow this caution may
result in personal injury. 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 heat pumps.
Examine all pipes, ttings, and valves before installing
any of the system components. Remove any dirt or debris
found in or on these components.
Pre-Installation - Installation, Operation, and
Maintenance instructions are provided with each
unit. Horizontal equipment is designed for installation
above false ceiling or in a ceiling plenum. Other unit
congurations are typically installed in a mechanical room.
The installation site chosen should include adequate
service clearance around the unit. Before unit start-up,
read all manuals and become familiar with the unit and its
operation. Thoroughly check the system before operation.
Prepare units for installation as follows:
1. Compare the electrical data on the unit nameplate with
ordering and shipping information to verify that the
correct unit has been shipped.
2. Keep the cabinet covered with the original packaging
until installation is complete and all plastering, painting,
etc. is nished.
3. Verify refrigerant tubing is free of kinks or dents and
that it does not touch other unit components.
4. Inspect all electrical connections. Connections must be
clean and tight at the terminals.
5. Remove any blower support packaging (water-to-air
units only).
6. Some airow patterns are eld convertible (horizontal
units only). Locate the airow conversion section of
this IOM.
7. Locate and verify any hot water generator (HWG),
hanger, or other accessory kit located in the
compressor section or blower section.
⚠ WARNING! ⚠
WARNING! Polyolester Oil, commonly known as POE oil, is
a synthetic oil used in many refrigeration systems including
those with HFC-410A refrigerant. POE oil, if it ever comes in
contact with the polymer drain pan, may cause the drain pan
to leak. The polymer drain pan should never come in contact
with POE oil as system failures and property damage may
result.

Installation, Operation, Maintenance
6
Installation, Operation & Maintenance - HEH/HEV Compact Series
Unit Physical Data
HE Two-Stage Series (60Hz Only)
Model 024 030 036 042 048 060
Compressor (1 Each) Scroll
Factory Charge HFC-410A (oz) 51 48 54 70 80 80
ECM Fan Motor & Blower
Fan Motor (hp) 1/2 1/2 1/2 3/4 3/4 1
Blower Wheel Size (dia x w) - (in) 9X7 9X7 9X8 9X8 10X10 11X10
Water Connection Size
FPT(in) 3/4” 3/4” 3/4” 3/4" 1" 1"
Coax Volume (gallons) 0.323 0.323 0.738 0.89 0.738 0.939
HWG Connection Size
FPT(in) 1/2”
Vertical Upow
Air Coil Dimensions (h x w) - (in) 20 X 17.25 20 X 17.25 24 X 21.75 24 X 21.75 28.75 X 24 28.75 X 24
Standard Filter - 1" [25.4mm] Throwaway, qty (in) 20x20 20x20 24x24 24x24 28x28 28x28
Weight - Operating, (lbs) 216 224 249 260 315 330
Weight - Packaged, (lbs) 221 229 255 266 322 337
Horizontal
Air Coil Dimensions (h x w) - (in) 16 X 22 16 X 22 20 X 25 20 X 25 20 X 35 20 X 35
Standard Filter - 1" [25.4mm] Throwaway, qty (in) 18x25 18x25 20x28 or
2-20x14
20x28 or
2-20x14
1-20x24,
1-20x14
1-20x24,
1-20x14
Weight - Operating, (lbs) 208 208 233 244 299 314
Weight - Packaged, (lbs) 213 213 239 250 306 321
Notes:
All units have TXV expansion device and 1/2” & 3/4” electrical knockouts.
Unit Maximum Water Working Pressure
Options Max Pressure PSIG [kPa]
Internal Pump
145 [999]
Internal Modulating Water Valve (MWV)
300 [2,068]

Installation, Operation, Maintenance 7
Installation, Operation & Maintenance - HEH/HEV Compact Series
Horizontal Installation
Mounting Horizontal Units
Horizontal units have 4 hanger brackets partially attached
at the factory, one at each corner. Enclosed within the unit
there is a hanger kit hardware bag containing vibration
isolation grommets, washers, screws and a hanger
installation instruction page. One additional screw from
the hardware bag must be added to each hanger bracket
before unit installation.Tighten each screw to 75 in-lbs
(8.5 Nm). See Figure 1. Refer to the hanger installation
instruction page contained in the hardware bag for details
of nal hanger bracket attachment and unit suspension.
See Figure 1a.
Use four (4) eld supplied threaded rods and factory
provided vibration isolators to suspend the unit. Safely
lift the unit into position supporting the bottom of the
unit. Ensure the top of the unit is not in contact with any
external objects. Connect the top end of the 4 all-thread
rods, slide rods through the brackets and grommet then
assemble washers and double nuts at each rod. Ensure
that the unit is approximately level and that the threaded
rod extends past the nuts.
Pitch the unit toward the drain as shown in Figure 2 to
improve the condensate drainage. On small units (less
than 2.5 tons/8.8kW) ensure that unit pitch does not
cause condensate leaks inside the cabinet.
Figure 1: Hanger Bracket
Horizontal Unit Location
Units are not designed for outdoor installation. Locate
the unit in an INDOOR area that allows enough space
for service personnel to perform typical maintenance or
repairs without removing unit from the ceiling. Horizontal
units are typically installed above a false ceiling or in a
ceiling plenum. Never install units in areas subject to
freezing or where humidity levels could cause cabinet
condensation (such as unconditioned spaces subject
to 100% outside air). Consideration should be given to
access for easy removal of the lter and access panels.
Provide sufcient room to make water, electrical, and duct
connection(s).
If the unit is located in a conned space, such as a closet,
provisions must be made for return air to freely enter the
space by means of a louvered door, etc. Any access panel
screws that would be difcult to remove after the unit is
installed should be removed prior to setting the unit. Refer
to Figure 3 for an illustration of a typical installation. Refer
to unit submittal data or engineering design guide for
dimensional data.
Conform to the following guidelines when selecting
unit location:
1. Provide a hinged access door in concealed-spline or
plaster ceilings. Provide removable ceiling tiles in T-bar
or lay-in ceilings. Refer to horizontal unit dimensions
for specic series and model in unit submittal data.
Size the access opening to accommodate the service
technician during the removal or replacement of the
compressor, control, or blower assembly.
2. Provide access to hanger brackets, water valves
and ttings. Provide screwdriver clearance to access
panels, discharge collars and all electrical connections.
3. DO NOT obstruct the space beneath the unit with
piping, electrical cables and other items that prohibit
future removal of components or the unit itself.
4. Use a manual portable jack/lift to lift and support the
weight of the unit during installation and servicing.
The installation of water source heat pump units and all
associated components, parts and accessories which
make up the installation shall be in accordance with the
regulations of ALL authorities having jurisdiction and MUST
conform to all applicable codes. It is the responsibility of
the installing contractor to determine and comply with ALL
applicable codes and regulations.
VIEW WATER CONNECTION END
FULLY ASSEMBLED
(Unit pictured for hanger bracket reference)
(Water hardware may vary per unit model)
ADD
BEFORE
HANGING
Figure 1a:
SCALE 1.000
DETAIL A

Installation, Operation, Maintenance
8
Installation, Operation & Maintenance - HEH/HEV Compact Series
Horizontal Installation, Cont’d.
Figure 3: Typical Horizontal Unit Installation
Air Coil - To obtain maximum performance, the air coil
should be cleaned before start-up. A 10% solution of
dishwasher detergent and water is recommended for
both sides of the coil. A thorough water rinse should
follow. UV based anti-bacterial systems may damage
coated air coils.
Notice! Installation Note - Ducted Return: Many
horizontal WSHPs are installed in a return air ceiling
plenum application (above ceiling). Vertical WSHPs are
commonly installed in a mechanical room with free return
(e.g. louvered door). Therefore, lter rails are the industry
standard and are included on Comfort-Aire/Century
commercial heat pumps for the purposes of holding the
lter only. For ducted return applications, the lter rail
must be removed and replaced with a duct ange or lter
frame. Canvas or exible connectors should also be used
to minimize vibration between the unit and ductwork.
(by others)
Thermostat
Wiring
Ball Valve with optional
integral P/T plug
Building
Loop
Unit Power
Disconnect
Power Wiring
Insulated supply duct with
at least one 90 deg elbow
to reduce air noise
Return Air
Supply Air
Unit Hanger Kits
(included)
3/8" [10mm] threaded rods
Unit Power
Stainless steel braid hose
with integral "J" swivel
Figure 2: Horizontal Unit Pitch
1/4” (6.4mm) pitch
toward drain for drainage
Drain Connection

Installation, Operation, Maintenance 9
Installation, Operation & Maintenance - HEH/HEV Compact Series
Field Conversion of Air Discharge
Water
Connection End
Return Air
Remove Screws
Water
Connection End
Return Air
Rotate
Move to Side
Side Discharge
Return Air
Water
Connection End
Discharge Air
Drain
Back Discharge
Replace Screws
Extremo de Con
Conducto de Alimentación
Retorno de Aire
Extremo de Conexión de Agua
Drenaje
Retorno de Aire
Descarga de Aire
Descarga Lateral
Water
Connection End
Supply Duct
Return Air
Water
Connection End
Drain
Return Air
Discharge Air
Side Discharge
Back Discharge
Overview - Horizontal units can be eld converted
between side (straight) and back (end) discharge using
the instructions below.
Note: It is not possible to eld convert return air
between left or right return models due to the
necessity of refrigeration copper piping changes.
Preparation - It is best to eld convert the unit on the
ground before hanging. If the unit is already hung it
should be taken down for the eld conversion.
Side to Back Discharge Conversion
1. Place unit in well lit area. Remove the screws as shown
in Figure 4 to free top panel and discharge panel.
2. Lift out the access panel and set aside. Lift and rotate
the discharge panel to the other position as shown,
being careful with the blower wiring.
3. Check blower wire routing and connections for
tension or contact with sheet metal edges. Re-route if
necessary.
4. Check refrigerant tubing for contact with other
components.
5. Reinstall top panel and screws noting that the location
for some screws will have changed.
6. Manually spin the fan wheel to ensure that the wheel
is not rubbing or obstructed.
7. Replace access panels.
Back to Side Discharge Conversion - If the discharge is
changed from back to side, use above instruction noting
that illustrations will be reversed.
Left vs. Right Return - It is not possible to eld convert
return air between left or right return models due to
the necessity of refrigeration copper piping changes.
However, the conversion process of side to back or
back to side discharge for either right or left return
conguration is the same. In some cases, it may be
possible to rotate the entire unit 180 degrees if the return
air connection needs to be on the opposite side. Note that
rotating the unit will move the piping to the other end
of the unit.
Figure 5: Right Return Side to Back
Figure 4: Left Return Side to Back

Installation, Operation, Maintenance
10
Installation, Operation & Maintenance - HEH/HEV Compact Series
Horizontal Installation
2”
1.5”
1.5”
1/8” Per
Foot
Figure 6: Horizontal Condensate Connection
CAUTION! Ensure condensate line is pitched toward drain
1/8 inch per ft [11mm per m] of run.
Condensate Piping - Horizontal Units - A condensate
drain line must be installed and pitched away for the unit
to allow for proper drainage. This connection must meet all
local plumbing/building codes.
Pitch the unit toward the drain as shown in Figure 2 to
improve the condensate drainage. On small units (less than
2.5 tons/8.8 kW), ensure that unit pitch does not cause
condensate leaks inside the cabinet.
Install condensate trap at each unit with the top of the trap
positioned below the unit condensate drain connection as
shown in Figure 6. Design the depth of the trap (water-
seal) based upon the amount of ESP capability of the
blower (where 2 inches [51 mm] of ESP capability requires
2 inches [51 mm] of trap depth). As a general rule, 1-1/2
inch [38 mm] trap depth is the minimum.
Each unit must be installed with its own individual trap and
connection to the condensate line (main) or riser. Provide
a means to ush or blow out the condensate line. DO NOT
install units with a common trap and/or vent.
Always vent the condensate line when dirt or air can
collect in the line or a long horizontal drain line is required.
Also vent when large units are working against higher
external static pressure than other units connected to the
same condensate main since this may cause poor drainage
for all units on the line. WHEN A VENT IS INSTALLED IN
THE DRAIN LINE, IT MUST BE LOCATED AFTER THE
TRAP IN THE DIRECTION OF THE CONDENSATE FLOW.
⚠ CAUTION! ⚠
Duct System Installation - Proper duct sizing and design
is critical to the performance of the unit. The duct system
should be designed to allow adequate and even airow
through the unit during operation. Air ow through the
unit MUST be at or above the minimum stated airow
for the unit to avoid equipment damage. Duct systems
should be designed for quiet operation. Refer to Figure 3
for horizontal duct system details or Figure 8 for vertical
duct system details. A exible connector is recommended
for both discharge and return air duct connections on
metal duct systems to eliminate the transfer of vibration
to the duct system. To maximize sound attenuation of
the unit blower, the supply and return plenums should
include internal berglass duct liner or be constructed
from ductboard for the rst few feet. Application of the
unit to uninsulated ductwork in an unconditioned space
is not recommended, as the unit’s performance may be
adversely affected.
At least one 90° elbow should be included in the supply
duct to reduce air noise. If air noise or excessive air ow is
a problem, the blower speed can be changed. For airow
charts, consult submittal data for the series and model of
the specic unit.
If the unit is connected to existing ductwork, a previous
check should have been made to ensure that the
ductwork has the capacity to handle the airow required
for the unit. If ducting is too small, as in the replacement
of a heating only system, larger ductwork should be
installed. All existing ductwork should be checked for
leaks and repaired as necessary.
Condensate drain connection is a rubber coupling that
couples to 3/4” schedule 40/80 PVC. Use hose clamps to
secure the pipe inside the coupling. If the connection is not
secure, the connection may leak.
Instructions for coupling the condensate drain to the trap
are included in the bag that includes the coupling and hose
clamps.
C o n d e n s a t e P i p i n g - H o r i z o n t a l U n i t s - A c o n d e n s a t e d r a i n l i n e m u s t b e i n s t a l l e d a n d p i t c h e d a w a y f o r t h e u n i t t o a l l o w f o r p r o p e r d r a i n a g e . T h i s c o n n e c t i o n m u s t m e e t a l l l o c a l p l u m b i n g / b u i l d i n g c o d e s . C o n d e n s a t e P i p i n g - H o r i z o n t a l U n i t s - A c o n d e n s a t e d r a i n l i n e m u s t b e i n s t a l l e d a n d p i t c h e d a w a y f o r t h e u n i t t o a l l o w f o r p r o p e r d r a i n a g e . T h i s c o n n e c t i o n m u s t m e e t a l l l o c a l p l u m b i n g / b u i l d i n g c o d e s . C o n d e n s a t e P i p i n g - H o r i z o n t a l U n i t s - A c o n d e n s a t e d r a i n l i n e m u s t b e i n s t a l l e d a n d p i t c h e d a w a y f o r t h e u n i t t o a l l o w f o r p r o p e r d r a i n a g e . T h i s c o n n e c t i o n m u s t m e e t a l l l o c a l p l u m b i n g / b u i l d i n g c o d e s .

Installation, Operation, Maintenance 11
Installation, Operation & Maintenance - HEH/HEV Compact Series
Vertical Installation
C o n d e n s a t e P i p i n g - H o r i z o n t a l U n i t s - A c o n d e n s a t e d r a i n l i n e m u s t b e i n s t a l l e d a n d p i t c h e d a w a y f o r t h e u n i t t o a l l o w f o r p r o p e r d r a i n a g e . T h i s c o n n e c t i o n m u s t m e e t a l l l o c a l p l u m b i n g / b u i l d i n g c o d e s . C o n d e n s a t e P i p i n g - H o r i z o n t a l U n i t s - A c o n d e n s a t e d r a i n l i n e m u s t b e i n s t a l l e d a n d p i t c h e d a w a y f o r t h e u n i t t o a l l o w f o r p r o p e r d r a i n a g e . T h i s c o n n e c t i o n m u s t m e e t a l l l o c a l p l u m b i n g / b u i l d i n g c o d e s . C o n d e n s a t e P i p i n g - H o r i z o n t a l U n i t s - A c o n d e n s a t e d r a i n l i n e m u s t b e i n s t a l l e d a n d p i t c h e d a w a y f o r t h e u n i t t o a l l o w f o r p r o p e r d r a i n a g e . T h i s c o n n e c t i o n m u s t m e e t a l l l o c a l p l u m b i n g / b u i l d i n g c o d e s .
Flexible canvas duct
connector to reduce
noise and vibration
Use turning vanes in
supply transition
Internally insulate return
transition duct to reduce noise Rev.: 2/13
Internally insulate supply
duct for the first 4’ (1.2m)
each way to reduce noise
Rounded return
transition
Remove supply duct
flanges from inside blower
compartment and install
on supply air opening of
unit. Do not use a supply
air plenum/duct smaller
than the size of the supply
duct flanges.
Flexible canvas duct
connector to reduce
noise and vibration
Use turning vanes in
supply transition
Internally insulate supply
duct for first 1.2 m each way
to reduce noise
Internally insulate return
transition duct to reduce noise
Rounded return
transition
Remove supply duct
flanges from inside blower
compartment and install
on supply air opening of
unit. Do not use a supply
air plenum/duct smaller
than the size of the supply
duct flanges.
Figure 7: Vertical Unit Mounting
Figure 8: Typical Vertical Unit Installation
Using Ducted Return Air
bloque o del ladrillo o sacado
Cojín del aire o sacado
Bloque o ladrillo concreto
Vibration Isolation Pad
Vertical Unit Location - Units are not designed for
outdoor installation. Locate the unit in an INDOOR area
that allows enough space for service personnel to perform
typical maintenance or repairs without removing unit from
the mechanical room/closet. Vertical units are typically
installed in a mechanical room or closet. Never install
units in areas subject to freezing or where humidity levels
could cause cabinet condensation (such as unconditioned
spaces subject to 100% outside air). Consideration
should be given to access for easy removal of the lter
and access panels. Provide sufcient room to make water,
electrical, and duct connection(s).
If the unit is located in a conned space, such as a closet,
provisions must be made for return air to freely enter the
space by means of a louvered door, etc. Any access panel
screws that would be difcult to remove after the unit is
installed should be removed prior to setting the unit. Refer
to Figures 7 and 8 for typical installation illustrations.
Refer to unit submittal data or engineering design guide
for dimensional data.
1. Install the unit on a piece of rubber, neoprene or other
mounting pad material for sound isolation. The pad
should be at least 3/8” [10 mm] to 1/2” [13 mm] in
thickness. Extend the pad beyond all four edges of
the unit.
2. Provide adequate clearance for lter replacement
and drain pan cleaning. Do not block lter access
with piping, conduit or other materials. Refer to
unit submittal data or engineering design guide for
dimensional data.
3. Provide access for fan and fan motor maintenance
and for servicing the compressor and coils without
removing the unit.
4. Provide an unobstructed path to the unit within the
closet or mechanical room. Space should be sufcient
to allow removal of the unit, if necessary.
5. Provide access to water valves and ttings and
screwdriver access to the unit side panels, discharge
collar and all electrical connections.
Notice! Installation Note - Ducted Return: Many
horizontal WSHPs are installed in a return air ceiling
plenum application (above ceiling). Vertical WSHPs are
commonly installed in a mechanical room with free return
(e.g. louvered door). Therefore, lter rails are the industry
standard and are included on Comfort-Aire/Century
commercial heat pumps for the purposes of holding the
lter only. For ducted return applications, the lter rail
must be removed and replaced with a duct ange or lter
frame. Canvas or exible connectors should also be used
to minimize vibration between the unit and ductwork.

Installation, Operation, Maintenance
12
Installation, Operation & Maintenance - HEH/HEV Compact Series
Vertical Installation, Cont’d.
Sound Attenuation for Vertical Units - Sound
attenuation is achieved by enclosing the unit within a
small mechanical room or a closet. Additional measures
for sound control include the following:
1. Mount the unit so that the return air inlet is 90° to the
return air grille. Refer to Figure 9. Install a sound bafe
as illustrated to reduce line-of sight sound transmitted
through return air grilles.
2. Mount the unit on a rubber or neoprene isolation pad
to minimize vibration transmission to the building
structure.
Return
Air Inlet
Figure 9: Vertical Sound Attenuation
Condensate Piping for Vertical Units - A condensate
line must be installed and pitched away from the unit to
allow for proper drainage. This connection must meet all
local plumbing/building codes.
Install condensate trap at each unit with the top of the trap
positioned below the unit condensate drain connection as
shown in Figure 10. Design the depth of the trap (water-
seal) based upon the amount of ESP capability of the
blower (where 2 inches [51mm] of ESP capability requires
2 inches [51mm] of trap depth).As a general rule, 1-1/2
inch [38mm] trap depth is the minimum.
Always vent the condensate line when dirt or air can
collect in the line or a long horizontal drain line is required.
Also vent when large units are working against higher
external static pressure than other units connected
to the same condensate main since this may cause
poor drainage for all units on the line. WHEN A VENT
IS INSTALLED IN THE DRAIN LINE, IT MUST BE
LOCATED AFTER THE TRAP IN THE DIRECTION OF
THE CONDENSATE FLOW.
Each unit must be installed with its own individual vent
(where necessary) and a means to ush or blow out the
condensate drain line. Do not install units with a common
trap and/or vent.
Condensate drain connection is a rubber coupling that
couples to 3/4” schedule 40/80 PVC. Use hose clamps to
secure the pipe inside the coupling. If the connection is
not secure, the connection may leak.
Instructions for coupling the condensate drain to the trap
are included in the bag that includes the coupling and
hose clamps.
Notice! Units with clear plastic drain lines should have
regular maintenance (as required) to avoid buildup of
debris, especially in new construction.

Installation, Operation, Maintenance 13
Installation, Operation & Maintenance - HEH/HEV Compact Series
Piping Installation
CAUTION! Corrosive system water requires corrosion
resistant ttings and hoses, and may require water treatment.
Table 1: Metal Hose Minimum Bend Radii
Hose Diameter Minimum Bend Radii
1/2" [12.7mm] 2-1/2" [6.4cm]
3/4" [19.1mm] 4" [10.2cm]
1" [25.4mm] 5-1/2" [14cm]
1-1/4" [31.8mm] 6-3/4" [17.1cm]
CAUTION! Do not bend or kink supply lines or hoses.
NOTICE! Do not allow hoses to rest against structural
building components. Compressor vibration may be
transmitted through the hoses to the structure, causing
unnecessary noise complaints.
Figure 11: Supply/Return Hose Kit
⚠ CAUTION! ⚠
⚠ CAUTION! ⚠
⚠ CAUTION! ⚠
Rib Crimped
Length
(2 ft [0.6m] Length Standard)
Swivel
Brass
Fitting
Brass
Fitting
MPT
Reborde Acanalado
Longitud
(Long. Estándar de 2 pies)
Accesorio
Giratorio
de Bronce
Accesorio
de Bronce
MPT
MPT
MPT
Rib Crimped
Length
(0.6m Length Standard)
Swivel
Brass
Fitting
Brass
Fitting
MPT
MPT
CAUTION! Piping must comply with all applicable codes.
Installation of Supply and Return Piping
Follow these piping guidelines.
1. Install a drain valve at the base of each supply and
return riser to facilitate system ushing.
2. Install shut-off / balancing valves and unions at each
unit to permit unit removal for servicing.
3. Place strainers at the inlet of each system circulating
pump.
4. Select the proper hose length to allow slack between
connection points. Hoses may vary in length by +2%
to -4% under pressure.
5. Refer to Table 1. Do not exceed the minimum bend
radius for the hose selected. Exceeding the minimum
bend radius may cause the hose to collapse, which
reduces water ow rate. Install an angle adapter to
avoid sharp bends in the hose when the radius falls
below the required minimum.
Insulation is not required on loop water piping except
where the piping runs through unheated areas, outside
the building or when the loop water temperature is below
the minimum expected dew point of the pipe ambient
conditions. Insulation is required if loop water temperature
drops below the dew point (insulation is required for
ground loop applications in most climates).
Pipe joint compound is not necessary when Teon®
thread tape is pre-applied to hose assemblies or when
ared-end connections are used. If pipe joint compound
is preferred, use compound only in small amounts on
the external pipe threads of the tting adapters. Prevent
sealant from reaching the ared surfaces of the joint.
Note: When antifreeze is used in the loop, ensure that
it is compatible with the Teon®tape or pipe joint com-
pound that is applied.
Maximum allowable torque for brass ttings is 30 ft-lbs
[41 N-m]. If a torque wrench is not available, tighten
nger-tight plus one quarter turn. Tighten steel ttings
as necessary.
Optional pressure-rated hose assemblies designed
specically for use with Comfort-Aire/Century units are
available. Similar hoses can be obtained from alternate
suppliers. Supply and return hoses are tted with
swivel-joint ttings at one end to prevent kinking during
installation.
Refer to Figure 11 for an illustration of a typical supply/
return hose kit. Adapters secure hose assemblies to the
unit and risers. Install hose assemblies properly and check
regularly to avoid system failure and reduced service life.
WARNING! Polyolester Oil, commonly known as POE oil, is
a synthetic oil used in many refrigeration systems including
those with HFC-410A refrigerant. POE oil, if it ever comes
in contact with PVC or CPVC piping, may cause failure of
the PVC/CPVC. PVC/CPVC piping should never be used
as supply or return water piping with water source heat
pump products containing HFC-410A as system failures and
property damage may result.
⚠ WARNING! ⚠

Installation, Operation, Maintenance
14
Installation, Operation & Maintenance - HEH/HEV Compact Series
Variable Flow Heat Pump Applications Overview
Variable ow is a revolutionary new, intelligent, and
efcient way to circulate water (or water plus antifreeze)
using internal, variable speed water ow control. The
factory installed high efciency variable speed pumps
uses almost half the wattage of traditional xed speed
pump. Variable ow technology improves the life
expectancy of the unit by reducing the amount of energy
required to optimize the ow of water throughout the
system and also reduces the space, cost, and labor
required to install external water ow control mechanisms
(ow controllers, solenoid and ow control valves).
Variable Flow Congurations:
1. Low System Pressure Drop Modulating Motorized
Valve – Typical for External Central Pumping.
Primarily for use on multi-unit applications with central
pumping. With this option the unit includes a low
pressure drop, high Cv modulating motorized water
valve that is controlled by the DXM2 control based
on the difference in the entering and leaving water
temperature delta T.
This valve is a standard factory installed feature for
the HE unit.
2. High System Pressure Drop Modulating Motorized
Valve – Typical for High Pressure Water System
such as Water Well Pumps.
With this option the unit includes a high pressure
drop modulating water valve that is controlled by the
DXM2 control based on the difference in the entering
and leaving water temperature delta T. A low Cv valve
is used to provide more precise control against high
system pressure differential type of loops. This valve
is a factory installed option for the HE unit and when
selected replaces the modulating valve.
3. Standard Head Variable Pump – Typical for
Multiple Unit Central Pumping.
With this option the unit includes an internal variable
speed pump that is best suited to low pressure drop
systems such as primary/secondary pumping. The
pump speed is controlled by the DXM2 control based
on the difference in the entering and leaving water
temperature delta T. This pump includes an internal
check valve for multiple unit installations.
This pump is a factory installed option for the HE unit
and when selected replaces the modulating valve.
4. High Head Variable Pump – Typical for Individual
Unit Pumping.
With this option the unit includes an internal variable
speed pump that is capable of higher system pressure
drops. The pump speed is controlled by the DXM2
control based on the difference in the entering
and leaving water temperature delta T. This pump
includes an internal check valve for multiple unit
installations. This pump is a factory installed option
for the HE unit and when selected replaces the
modulating valve.
High and
Low Voltage
Knockouts
Vibration Isolation Pad
To Thermostat
Internal Motorized
Modulating Valve
Water Out
Shut Off
Ball Valves
for Isolation
Water In
Pressure
Tank
Optional
Filter
Boiler
Drains
Typical Closed-Loop Application (with Internal Variable
Pump Shown)
High and
Low Voltage
Knockouts
Vibration Isolation Pad
To Thermostat
Internal Variable
Pump
Water In
Water Out
Typical Open Loop Application (with Internal
Modulating Motorized Valve Shown)
For use on applications using external source for ow.
Variable speed pump or motorized modulating valve delivers variable
water-ow, controlled by DXM2 control, based on loop water ∆T.

Installation, Operation, Maintenance 15
Installation, Operation & Maintenance - HEH/HEV Compact Series
Variable Flow Heat Pump Applications Overview, Cont’d.
Water Pressure Schrader Ports
The pressure ports built in to the unit are provided as a
means of measuring pressure drop through the water-
to-refrigerant heat exchanger. The water pressure ports
are schrader ports smaller than refrigerant schrader ports.
They are the same size as tire schrader ports. A digital
pressure gauge is recommended for taking pressure
readings through these ports. The water ow through
High System Pressure Drop Valve Low System Pressure Drop Valve
Model CV MOPD WPD Adders
GPM PSI FT
024
4.7 200 3.0 0.41 0.94
4.7 200 4.5 0.92 2.12
4.7 200 6.0 1.63 3.76
030
4.7 200 3.8 0.65 1.51
4.7 200 5.6 1.42 3.28
4.7 200 7.5 2.55 5.88
036
4.7 200 4.5 0.92 2.12
4.7 200 6.8 2.09 4.84
4.7 200 9.0 3.67 8.47
042
4.7 200 5.3 1.27 2.94
4.7 200 7.9 2.83 6.53
4.7 200 10.5 4.99 11.53
048
4.7 200 6.0 1.63 3.76
4.7 200 9.0 3.67 8.47
4.7 200 12.0 6.52 15.06
060
7.4 200 7.0 .89 2.06
7.4 200 10.5 2.01 4.64
7.4 200 14.0 3.58 8.26
Model CV MOPD WPD Adders
GPM PSI FT
024
4.7 200 3.0 0.41 0.94
4.7 200 4.5 0.92 2.12
4.7 200 6.0 1.63 3.76
030
7.4 200 3.8 0.26 0.61
7.4 200 5.6 0.57 1.32
7.4 200 7.5 1.03 2.37
036
7.4 200 4.5 0.37 0.85
7.4 200 6.8 0.84 1.95
7.4 200 9.0 1.48 3.42
042
10.0 200 5.3 0.28 0.65
10.0 200 7.9 0.62 1.44
10.0 200 10.5 1.10 2.55
048
10.0 200 6.0 0.36 0.83
10.0 200 9.0 0.81 1.87
10.0 200 12.0 1.44 3.33
060
19.0 200 7.0 0.14 0.31
19.0 200 10.5 0.31 0.70
19.0 200 14.0 0.54 1.25
the unit can be determined by measuring the water
pressure at the “water pressure out” port and subtracting
it from the water pressure at the “water pressure in”
port. Comparing the pressure differential to the pressure
drop table (wpd)/ow rate in Table 10 in this manual will
determine the ow rate through the unit.
Standard Head Variable Pump Performance
0
5
10
15
20
25
30
35
0 5 10 15 20
Head (.)
Flow Rate (gpm)
No Check
Valve
With Check
Valve

Installation, Operation, Maintenance
16
Installation, Operation & Maintenance - HEH/HEV Compact Series
High Head Variable Pump Performance
0
5
10
15
20
25
30
35
40
45
0 5 10 15 20 25
Head (.)
Flow (gpm)
No Check
Valve
With Check
Valve

Installation, Operation, Maintenance 17
Installation, Operation & Maintenance - HEH/HEV Compact Series
Water-Loop Heat Pump Applications
Commercial Water Loop Applications
Commercial systems typically include a number of units
connected to a common piping system. Any unit plumbing
maintenance work can introduce air into the piping system;
therefore air elimination equipment is a major portion of the
mechanical room plumbing. Consideration should be given
to insulating the piping surfaces to avoid condensation.
Comfort-Aire/Century recommends unit insulation any
time the water temperature is expected to be below 60ºF
(15.6ºC). Metal to plastic threaded joints should never be
used due to their tendency to leak over time.
Teon®tape thread sealant is recommended to minimize
internal fouling of the heat exchanger. Do not over tighten
connections and route piping so as not to interfere with
service or maintenance access. Hose kits are available
from Comfort-Aire/Century in different congurations
for connection between the unit and the piping system.
Depending upon selection, hose kits may include shut
off valves, P/T plugs for performance measurement, high
pressure stainless steel braided hose, “Y” type strainer with
blow down valve, and/or with blow down valve, auto-ow
valve and swivel connections.
The piping system should be ushed to remove dirt, piping
chips, and other foreign material prior to operation (see
“Piping System Cleaning and Flushing Procedures” in this
manual). The ow rate is usually set between 2.25 and 3.5
gpm per ton [2.9 and 4.5 l/m per kW] of cooling capacity.
Comfort-Aire/Century recommends 3 gpm per ton [3.9 l/m
per kW] for most applications of water loop heat pumps.
To ensure proper maintenance and servicing, P/T ports are
imperative for temperature and ow verication, as well as
performance checks.
Water loop heat pump (cooling tower/boiler) systems
typically utilize a common loop, maintained between
60 - 90°F [16 - 32°C]. The use of a closed circuit
evaporative cooling tower with a secondary heat
exchanger between the tower and the water loop is
recommended. If an open type cooling tower is used
continuously, chemical treatment and ltering will be
necessary.
Typical Water-Loop Application
(by others)
Thermostat
Wiring
Ball Valve with optional
integral P/T plug
Building
Loop
Unit Power
Disconnect
Power Wiring
Insulated supply duct with
at least one 90 deg elbow
to reduce air noise
Return Air
Supply Air
Unit Hanger Kits
(included)
3/8" [10mm] threaded rods
Unit Power
Stainless steel braid hose
with integral "J" swivel
Low Water Temperature Cutout Setting - DXM2 Control
When antifreeze is selected, the LT1 jumper (JW3) should be clipped to select the low temperature (antifreeze 10.0°F
[-12.2°C]) setpoint and avoid nuisance faults (see “Low Water Temperature Cutout Selection” in this manual). Note:
Low water temperature operation requires extended range equipment.

Installation, Operation, Maintenance
18
Installation, Operation & Maintenance - HEH/HEV Compact Series
Ground-Loop Heat Pump Applications
Pre-Installation
Prior to installation, locate and mark all existing
underground utilities, piping, etc. Install loops for new
construction before sidewalks, patios, driveways, and other
construction has begun. During construction, accurately
mark all ground loop piping on the plot plan as an aid in
avoiding potential future damage to the installation.
Piping Installation
All earth loop piping materials should be limited to
polyethylene fusion only for in-ground sections of the
loop. Galvanized or steel ttings should not be used at any
time due to their tendency to corrode. All plastic to metal
threaded ttings should be avoided due to their potential
to leak. A anged tting should be substituted. P/T plugs
should be used with units that do not include variable ow
so that ow can be measured using the pressure drop of
the unit heat exchanger. Units equipped with any of the
four variable ow congurations have built in Schrader
ports. Water temperature may be viewed on the intelligent
communicating thermostat.
Earth loop temperatures can range between 25 and 110°F
[-4 to 43°C]. Flow rates between 2.25 and 3 gpm [2.41 to
3.23 l/m per kW] of cooling capacity is recommended in
these applications.
Test individual horizontal loop circuits before backlling.
Test vertical U-bends and pond loop assemblies prior to
installation. Pressures of at least 100 psi [689 kPa] should
be used when testing. Do not exceed the pipe pressure
rating. Test entire system when all loops are assembled.
Flushing the Earth Loop
Upon completion of system installation and testing, ush
the system to remove all foreign objects and purge to
remove all air.
Antifreeze
I n areas where minimum entering loop temperatures
drop below 40°F [5°C] or where piping will be routed
through areas subject to freezing, antifreeze is required.
Alcohols and glycols are commonly used as antifreeze;
however your local sales ofce should be consulted to
determine the antifreeze best suited to your area. Freeze
protection should be maintained to 15°F [9°C] below the
lowest expected entering loop temperature. For example,
if 30°F [-1°C] is the minimum expected entering loop
temperature, the leaving loop temperature would be 22 to
25°F [-6 to -4°C] and freeze protection should be at 15°F
[-10°C]. Calculation is as follows:
30°F - 15°F = 15°F [-1°C - 9°C = -10°C].
All alcohols should be premixed and pumped from
a reservoir outside of the building when possible or
introduced under the water level to prevent fumes.
Calculate the total volume of uid in the piping system.
Then use the percentage by volume shown in table 2 for
the amount of antifreeze needed. Antifreeze concentration
should be checked from a well mixed sample using a
hydrometer to measure specic gravity.
CAUTION! The following instructions represent industry
accepted installation practices for closed loop earth coupled
heat pump systems. Instructions are provided to assist the
contractor in installing trouble free ground loops. These
instructions are recommendations only. State/provincial
and local codes MUST be followed and installation MUST
conform to ALL applicable codes. It is the responsibility of
the installing contractor to determine and comply with ALL
applicable codes and regulations.
Table 2: Antifreeze Percentages by Volume
Low Water Temperature Cutout Setting - DXM2
Control
When antifreeze is selected, the LT1 jumper (JW3) should
be clipped to select the low temperature (antifreeze
10.0°F [-12.2°C]) setpoint and avoid nuisance faults
(see “Low Water Temperature Cutout Selection” in this
manual). Note: Low water temperature operation
requires extended range equipment.
⚠ CAUTION! ⚠
⚠ CAUTION! ⚠
Type Minimum Temperature for Low Temperature Protection
10°F [-12.2°C] 15°F [-9.4°C] 20°F [-6.7°C] 25°F [-3.9°C]
Methanol
100% USP food grade Propylene Glycol
Ethanol*
25%
38%
29%
21%
25%
25%
16%
22%
20%
10%
15%
14%
CAUTION! Ground loop applications require extended range
equipment and optional refrigerant/water circuit insulation.
* Must not be denatured with any petroleum based product

Installation, Operation, Maintenance 19
Installation, Operation & Maintenance - HEH/HEV Compact Series
Ground-Loop and Ground-Water Heat Pump Applications
Ground Water Heat Pump Applications
Typical Open Loop/Well (unit with internal
modulating water valve)
High and
Low Voltage
Knockouts
Vibration Isolation Pad
To Thermostat
Internal Motorized
Modulating Valve
Water Out
Shut Off
Ball Valves
for Isolation
Water In
Pressure
Tank
Optional
Filter
Boiler
Drains
High and
Low Voltage
Knockouts
Vibration Isolation Pad
To Thermostat
Internal Motorized
Modulating Valve
Water Out
Shut Off
Ball Valves
for Isolation
Water In
Ground-Loop Heat Pump Applications
Typical Closed Loop with Central Pumping (unit with
internal modulating water valve)

Installation, Operation, Maintenance
20
Installation, Operation & Maintenance - HEH/HEV Compact Series
Ground-Water Heat Pump Applications
Open Loop - Ground Water Systems - Typical open
loop piping is shown in accompanying illustration. Shut off
valves should be included for ease of servicing. Boiler drains
or other valves should be “tee’d” into the lines to allow acid
ushing of the heat exchanger. Shut off valves should be
positioned to allow ow through the coax via the boiler
drains without allowing ow into the piping system. P/T
plugs should be used with units that do not include variable
ow so that flow can be measured using the pressure drop
of the unit heat exchanger. Units equipped with any of the
four variable ow configurations have built in Schrader
ports. Water temperature may be viewed on the intelligent
communicating thermostat. Supply and return water piping
should be limited to copper, HPDE, or other acceptable
high temperature material.
Note that PVC or CPVC material
is not recommended as they are not compatible with the
polyolester oil used in HFC-410A products.
Water quantity should be plentiful and of good quality.
Consult table 3 for water quality guidelines. The unit can
be ordered with either a copper or cupro-nickel water
heat exchanger. Consult Table 3 for recommendations.
Copper is recommended for closed loop systems and open
loop ground water systems that are not high in mineral
content or corrosiveness. In conditions anticipating heavy
scale formation or in brackish water, a cupro-nickel heat
exchanger is recommended. In ground water situations
where scaling could be heavy or where biological growth
such as iron bacteria will be present, an open loop system
is not recommended. Heat exchanger coils may over time
lose heat exchange capabilities due to build up of mineral
deposits. Heat exchangers must only be serviced by a
qualied technician, as acid and special pumping equipment
is required. Desuperheater coils can likewise become scaled
and possibly plugged. In areas with extremely hard water,
the owner should be informed that the heat exchanger
may require occasional acid ushing. In some cases, the
desuperheater option should not be recommended due to
hard water conditions and additional maintenance required.
Water Quality Standards - Table 3 should be consulted
for water quality requirements. Scaling potential should
be assessed using the pH/Calcium hardness method. If
the pH <7.5 and the calcium hardness is less than 100
ppm, scaling potential is low. If this method yields numbers
out of range of those listed, the Ryznar Stability and
Langelier Saturation indecies should be calculated. Use the
appropriate scaling surface temperature for the application,
150°F [66°C] for direct use (well water/open loop) and
DHW (desuperheater); 90°F [32°F] for indirect use. A
monitoring plan should be implemented in these probable
scaling situations. Other water quality issues such as iron
fouling, corrosion prevention and erosion and clogging
should be referenced in Table 3.
Expansion Tank and Pump - Use a closed, bladder-type
expansion tank to minimize mineral formation due to air
exposure. The expansion tank should be sized to provide at
least one minute continuous run time of the pump using its
drawdown capacity rating to prevent pump short cycling.
Discharge water from the unit is not contaminated in any
manner and can be disposed of in various ways, depending
on local building codes (e.g. recharge well, storm sewer,
drain eld, adjacent stream or pond, etc.). Most local codes
forbid the use of sanitary sewer for disposal. Consult your
local building and zoning department to assure compliance
in your area.
Water Control Valve - Units without Variable Flow -
Always maintain water pressure in the heat exchanger
by placing the water control valve(s) on the discharge line
to prevent mineral precipitation during the off-cycle. Pilot
operated slow closing valves are recommended to reduce
water hammer. If water hammer persists, a mini-expansion
tank can be mounted on the piping to help absorb the
excess hammer shock. Ensure that the total ‘VA’ draw of the
valve can be supplied by the unit transformer. For instance,
a slow closing valve can draw up to 35VA. A typical pilot
operated solenoid valve draws approximately 15VA. Note
the special wiring diagrams for slow closing valves (shown
later in this manual).
WARNING! Polyolester Oil, commonly known as POE oil, is
a synthetic oil used in many refrigeration systems including
those with HFC-410A refrigerant. POE oil, if it ever comes
in contact with PVC or CPVC piping, may cause failure of
the PVC/CPVC. PVC/CPVC piping should never be used
as supply or return water piping with water source heat
pump products containing HFC-410A as system failures and
property damage may result.
⚠ WARNING!