Bard WH423D User manual

Manual 2100-488
Page 1 of 26
WALL MOUNTED
PACKAGE HEAT PUMPS
MODELS:
WH423D
WH484D
WH604D
INSTALLATION INSTRUCTIONS
Manual : 2100-488
Supersedes: NEW
File: Volume III Tab 17
Date: 01-04-08
Bard Manufacturing Company, Inc.
Bryan, Ohio 43506
Since 1914...Moving ahead just as planned.

Manual 2100-488
Page 2 of 26
Contents
Getting Other Informations and Publications
For more information, contact these publishers:...... 3
Wall Mount General Information
Heat Pump Wall Mount Model Nomenclature.......... 4
Shipping Damage .................................................... 7
General ................................................................ 7
Duct Work................................................................ 7
Filters ................................................................ 7
Fresh Air Intake ....................................................... 8
Condensate Drain.................................................... 8
Installation Instructions
Wall Mounting Information....................................... 9
Mounting the Unit .................................................... 9
Typical Installations ................................................. 9
Wiring – Main Power ............................................. 13
Wiring – Low Voltage............................................. 13
Low Voltage Connections ...................................... 13
Thermostat Indicators ............................................ 16
Start Up
Important Installer Note ......................................... 17
Crankcase Heaters................................................ 17
High Pressure Switch ............................................ 17
Three Phase Scroll Compressor Start Up.............. 17
Phase Monitor ....................................................... 18
Service Hints ......................................................... 18
Sequence of Operation.......................................... 18
Pressure Service Ports.......................................... 18
Defrost Cycle ......................................................... 19
Troubleshooting
Solid State Heat Pump Control
Troubleshooting Procedure................................ 20
Checking Temperature Sensor
Outside Unit Circuit............................................ 21
Temperature vs. Resistance of
Temperature Sensor .......................................... 21
Fan Blade Dimensions .......................................... 22
Removal of Fan Shroud......................................... 22
Refrigerant Charge ................................................ 22
Pressure Tables ................................................ 23-24
Optional Accessories ............................................. 24
Figures
Figure 1 Unit Dimensions...................................... 5
Figure 2 Blower Damper Assembly ....................... 8
Figure 3 Mounting Instructions............................ 10
Figure 4 Electric Heat Clearance ........................ 10
Figure 5 Wall Mounting Instructions.....................11
Figure 6 Wall Mounting Instructions.....................11
Figure 7 Common Wall Mounting Installations.... 12
Figure 8 Hot Gas Reheat During
Dehumidification with CS2000A ........ 14
Figure 9 Hot Gas Reheat During
Dehumidification with
Programmable Thermostat ................ 15
Figure 10 Start Up Label ....................................... 17
Figure 11 Defrost Control Board ........................... 19
Figure 12 Fan Blade Setting ................................. 22
Figure 13 Circuit Diagram Heat Pump
Cooling Mode........................................ 26
Figure 14 Circuit Diagram Heat Pump
Dehumidification Mode ......................... 26
Tables
Table 1 Electric Heat Table .................................. 4
Table 2 Electrical Specifications .......................... 6
Table 3 Thermostat Wire Size ........................... 16
Table 4 Wall Thermostats .................................. 16
Table 5 Troubleshooting .................................... 20
Table 6 Fan Blade Dimensions.......................... 22
Table 7 Suction Line Temperatures ................... 22
Table 8 Recommended Operating Ranges ....... 22
Table 9 Indoor Blower Performance .................. 22
Table 10 Maximum ESP of Operation.................. 23
Table 11 Pressure Table – Cooling...................... 23
Table 12 Pressure Table – Heating...................... 24
Table 13 Optional Accessories ............................ 24
Table 14 Dehumidification Relay Logic Board..... 25

Manual 2100-488
Page 3 of 26
Getting Other Information and Publications
These publications can help you install the air
conditioner or heat pump. You can usually find these at
your local library or purchase them directly from the
publisher. Be sure to consult current edition of each
standard.
National Electrical Code ....................... ANSI/NFPA70
Standard for the Installation ............... ANSI/NFPA 90A
of Air Conditioning and Ventilating Systems
Standard for Warm Air ........................ANSI/NFPA90B
Heating and Air Conditioning Systems
Load Calculation for .....................ACCA Manual J or N
Residential Winter and Summer Air Conditioning
Low Pressure, Low Velocity ...... ACCA Manual D or Q
Duct System Design for Winter and Summer Air
Conditioning
For more information, contact these
publishers:
ACCA Air Conditioning Contractors of America
1712 New Hampshire Ave. N.W.
Washington, DC 20009
Telephone: [phone]
Fax: [phone]
ANSI American National Standards Institute
11 West Street, 13th Floor
New York, NY 10036
Telephone: [phone]
Fax: [phone]
ASHRAE American Society of Heating Refrigerating
and Air Conditioning Engineers, Inc.
1791 Tullie Circle, N.E.
Atlanta, GA 30329-2305
Telephone: [phone]
Fax: [phone]
NFPA National Fire Protection Association
Batterymarch Park
P.O. Box 9101
Quincy, MA 02269-9901
Telephone: [phone]
Fax: [phone]

Manual 2100-488
Page 4 of 26
WALLMOUNT GENERALINFORMATION
Heat Pump Wall Mount Model Nomenclature
WH 48 4 D A 10 X X X X X B
TABLE 1
ELECTRICHEATTABLE
sledoMAD324HW BD324HW BD484HWCD324HW AD484HW AD406HW BD484HW BD406HW CD484HW CD406HW
WK
1-0421-8023-0423-8023-0641-0421-8023-0423-8023-064
AUTBAUTBAUTBAUTBAUTBAUTBAUTBAUTBAUTBAUTB
58.02560711.81008218.02560711.8100821
64.41005025.21063512.708402
97.12006037.81030328.01007037.12006037.81030328.0100703
016.14031432.63006526.14031432.6300652
CONTROL
MODULES
NOTE: For 0 KW and circuit breakers (230/208V) or pull disconnects (460V) applications, insert 0Z in the KW field of model number.
MODEL
NUMBER
CAPACITY
42 – 3½ Ton
48 – 4 Ton
60 – 5 Ton
REVISION
COIL OPTIONS
X – Standard
1 – Phenolic Coated Evaporator
2 – Phenolic Coated Condenser
3 – Phenolic Coated Evaporator
and Condenser
OUTLET OPTIONS
X – Front (Standard)
COLOR OPTIONS
X – Beige (Standard)
1 – White
2 – Mesa Tan
4 – Buckeye Gray
FILTER OPTIONS
X – 1-Inch Throwaway
(Standard)
W – 1-Inch Washable
P – 2-Inch Pleated
VENTILATION OPTIONS
X –Barometric Fresh Air Damper (Standard)
B – Blank-off Plate
M – Motorized Fresh Air Damper
V – Commercial Room Ventilator - Motorized with Exhaust
E – Economizer (Internal) - Fully Modulating with Exhaust
R – Energy Recovery Ventilator - Motorized with Exhaust
KW
00 – No KW
05 – 5 KW
06 – 6 KW
09 – 9 KW
10 – 10 KW
DEHUMIDIFICATION
REHEAT CIRCUIT
VOLTS & PHASE
A – 230/208/60-1
B – 230/208/60-3
C – 460/60-3

Manual 2100-488
Page 5 of 26
FIGURE 1
UNITDIMENSIONS

Manual 2100-488
Page 6 of 26
1Maximum size of the time delay fuse or HACR type circuit breaker for protection of field wiring conductors.
2Based on 75°C copper wire. All wiring must conform to NEC and all local codes.
3Maximum KW that can operate with heat pump on. These "Minimum Circuit Ampacity" values are to be used for sizing the field
power conductors. Refer to the National Electrical Code (latest version), article 310 for power conductor sizing.
CAUTION: When more than one field power conductor circuit is run through one conduit, the conductors must be derated.
Pay special attention to note 8 of table 310 regarding Ampacity Adjustment Factors when more than 3
conductors are in a raceway.
TABLE 2
ELECTRICALSPECIFICATIONS
ledoM
TIUCRICELGNIS TIUCRICLAUD
detaR &stloV esahP
.oN dleiF rewoP .stkC
4
muminiM tiucriC yticapmA
1
mumixaM lanretxE roesuF tiucriC rekaerB
2
dleiF rewoP eriW eziS
2
dnuorG eriW eziS
4
muminiM tiucriC yticapmA
1
mumixaM lanretxE .tkCroesuF rekaerB
2
rewoPdleiF eziSeriW
2
eriWdnuorG eziS
AtkCBtkCAtkCBtkCAtkCBtkCAtkCBtkC
Z0A,00AD324HW 50A
3 01A 1-802/032 12ro1 2ro1
430668
050709
8
6
3
01
8
8
A/N4343
A/N6225
A/N0505
A/N0306
A/N8
8
A/N01
6
A/N0101
A/N0101
Z0B,00BD324
HW 60B
3 90B 3-802/032 1
1
1
624435
530506
8
8
6
010101
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A
/N A/N
Z0C,00CD324HW 60C
3 90C 3-064 1
1
1
313272
025203
210101
210101
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A
/N A/N
Z0A,00AD484HW 50A
3 01A 1-802/032 12ro1 2ro1
834609
0508 001
8
6
3
01
8
8
A/N8383
A/N6225
A/N0606
A/N0306
A/N8
8
A/N01
6
A/N0101
A/N0101
Z0B,00BD48
4HW 60B
3 90B 3-802/032 1
1
1
725445
530506
8
8
6
010101
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A/N A/N
A/N A
/N A/N
Z0C,00CD484HW
3 90C 3-064 1
15182 0203 2101 2101 A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N
Z0A,00AD406HW 50A
3 01A 1-802/032 12ro1 2ro1
541779
0609 011
8
4
3
01
8
6
A/N5454
A/N6225
A/N0606
A/N0606
A/N8
8
A/N01
6
A/N0101
A/N0101
Z0B,00BD4
06HW
3 90B 3-802/032 1
13306 5406 8 60101 A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N
Z0C,00CD406HW
3 90C 064 1
16192 0253 21 82101 A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N A/N

Manual 2100-488
Page 7 of 26
SHIPPINGDAMAGE
Upon receipt of equipment, the carton should be checked
for external signs of shipping damage. If damage is
found, the receiving party must contact the last carrier
immediately, preferably in writing, requesting inspection
by the carrier’s agent.
GENERAL
The equipment covered in this manual is to be installed
by trained, experienced service and installation
technicians.
The refrigerant system is completely assembled and
charged. All internal wiring is complete.
The unit is designed for use with or without duct work.
Flanges are provided for attaching the supply and return
ducts.
These instructions and any instructions packaged with
any separate equipment required to make up the entire
heat pump system should be carefully read before
beginning the installation. Note particularly “Starting
Procedure” and any tags and/or labels attached to the
equipment.
While these instructions are intended as a general
recommended guide, they do not supersede any national
and/or local codes in any way. Authorities having
jurisdiction should be consulted before the installation
is made. See Page 3 for information on codes and
standards.
Size of unit for a proposed installation should be based
on heat loss calculation made according to methods of
Air Conditioning Contractors of America (ACCA). The
air duct should be installed in accordance with the
Standards of the National Fire Protection Association
for the Installation of Air Conditioning and Ventilating
Systems of Other Than Residence Type, NFPA No.
90A, and Residence Type Warm Air Heating and Air
Conditioning Systems, NFPA No. 90B. Where local
regulations are at a variance with instructions, installer
should adhere to local codes.
DUCT WORK
Any heat pump is more critical of proper operating
charge and an adequate duct system than a straight air
conditioning unit. All duct work, supply and return,
must be properly sized for the design airflow
requirement of the equipment. Air Conditioning
Contractors of America (ACCA) is an excellent guide to
proper sizing. All duct work or portions thereof not in
the conditioned space should be properly insulated in
order to both conserve energy and prevent condensation
or moisture damage.
Any grille that meets the 5/8 inch louver criteria, may be
used. It is recommended that Bard Return Air Grille Kit
RG-2 through RG-5 or RFG-2 through RFG-5 be
installed when no return duct is used. Contact
distributor or factory for ordering information. If using a
return air filter grille, filters must be of sufficient size to
allow a maximum velocity of 400 fpm.
NOTE: If no return air duct is used, applicable
installation codes may limit this cabinet to
installation only in a single story structure.
FILTERS
A 1-inch throwaway filter is supplied with each unit.
The filter slides into position making it easy to service.
This filter can be serviced from the outside by removing
the service door. A 1-inch washable filter and 2-inch
pleated filter are also available as optional accessories.
The internal filter brackets are adjustable to
accommodate the 2-inch filter by bending down the tabs
to allow spacing for the 2-inch filters.
Refer to Table 10 for maximum static pressure available
for duct design.
Design the duct work according to methods given by the
Air Conditioning Contractors of America (ACCA).
When duct runs through unheated spaces, it should be
insulated with a minimum of one inch of insulation. Use
insulation with a vapor barrier on the outside of the
insulation. Flexible joints should be used to connect the
duct work to the equipment in order to keep the noise
transmission to a minimum.
A 1/4 inch clearance to combustible material for the
first three feet (3') of duct attached to the outlet air
frame is required. See Wall Mounting Instructions and
Figures 3, 4, 5 and 6 for further details.
Ducts through the walls must be insulated and all joints
taped or sealed to prevent air or moisture entering the
wall cavity.
CAUTION
Some installations may not require any return
air duct. A metallic return air grille is required
with installations not requiring a return air duct.
The spacing between louvers on the grille shall
not be larger than 5/8 inches.

Manual 2100-488
Page 8 of 26
FRESH AIR INTAKE
All units are built with fresh air inlet slots punched in
the service panel.
If the unit is equipped with the fresh air damper
assembly, the assembly is shipped already attached to
the unit. The damper blade is locked in the closed
position. To allow the damper to operate, the
maximum and minium blade position stops must be
installed. See Figure 2.
All capacity, efficiency and cost of operation
information as required for Department of Energy
“Energyguide” Fact Sheets is based upon the fresh air
blank-off plate in place and is recommended for
maximum energy efficiency.
The blank-off plate is available upon request from the
factory and is installed in place of the fresh air damper
shipped with each unit.
CONDENSATE DRAIN
A plastic drain hose extends from the drain pan at the
top of the unit down to the unit base. There are
openings in the unit base for the drain hose to pass
through. In the event the drain hose is connected to a
drain system of some type, it must be an open or vented
type system to assure proper drainage.
FIGURE 2
BLOWERDAMPERASSEMBLY

Manual 2100-488
Page 9 of 26
INSTALLATION INSTRUCTIONS
WALLMOUNTINGINFORMATION
1. Two holes, for the supply and return air openings,
must be cut through the wall as shown in Figure 3.
2. On wood-frame walls, the wall construction must be
strong and rigid enough to carry the weight of the
unit without transmitting any unit vibration. See
Figures 5 and 6.
3. Concrete block walls must be thoroughly inspected
to insure that they are capable of carrying the weight
of the installing unit. See Figure 4.
MOUNTING THE UNIT
1. These units are secured by wall mounting brackets,
which secure the unit to the outside wall surface at
both sides. A bottom mounting bracket is provided
for ease of installation, but it is not required.
2. The unit itself is suitable for “0” inch clearance, but
the supply air duct flange and the first 3 feet of
supply air duct require a minimum of 1/4 inch
clearance to combustible material. If a combustible
wall, use a minimum of 30½" x 10½" dimensions for
sizing. However, it is generally recommended that a
1-inch clearance is used for ease of installation and
maintaining the required clearance to combustible
material. The supply air opening would then be
32" x 12". See Figures 3, 4 and 7 for details.
3. Locate and mark lag bolt locations and bottom
mounting bracket location. See Figure 4.
4. Mount bottom mounting bracket.
5. Hook top rain flashing under back bend of top. Top
rain flashing is shipped secured to the right side of the
back.
6. Position unit in opening and secure with 5/16 lag
bolts; use 7/8 inch diameter flat washers on the lag
bolts.
7. Secure rain flashing to wall and caulk across entire
length of top. See Figure 3.
8. For additional mounting rigidity, the return air and
supply air frames or collars can be drilled and
screwed or welded to the structural wall itself
(depending upon wall construction). Be sure to
observe required clearance if combustible wall.
9. On side-by-side installations, maintain a minimum of
20 inches clearance on right side to allow access to
heat strips and control panel, and to allow proper
airflow to the outdoor coil. Additional clearance may
be required to meet local or national codes.
TYPICAL INSTALLATIONS
See Figure 7 for common ways to install the Wall
Mount unit.
WARNING
Fire hazard can result if 1/4 inch clearance to
combustible materials for supply air duct is not
maintained. See Figure 3.
WARNING
Failure to provide the 1/4 inch clearance
between the supply duct and a combustible
surface for the first 3 feet of duct can result in
fire.

Manual 2100-488
Page 10 of 26
FIGURE 3
MOUNTINGINSTRUCTIONS
FIGURE 4
ELECTRICHEAT CLEARANCE
6 5/8" 6 5/8"
1 7/8"
21"
21"
16"
16"
16"
DIM. "D"
DIM. "B"
DIM. "E"
16"
DIM. "A"DIM. "C" DIM. "C"
30"
Supply Opening
Return Opening
Wall Bracket
Wall
Mounting
Hole
Pattern
Front view of wall with unit removed
1/4" clearance on
all (4) sides of
supply air duct
is required from
combustible
materials
Supply
Air Duct
Return
Air Opening
Wall
Circuit breaker
access door
Heater access
panel Note: It is recommended
that a bead of silicone
caulking be placed behind
the side mounting flanges
and under top flashing at
time of installation.
MIS-796 A
Top flashing detail view
Attach supplied
rain flashing.
Apply caulk
between flashing
and wall.
Foam air seal
Seal with bead of
caulking along entire
length of top.
Supply flange
Side view of wall with unit installed
DIM. "A" DIM. "B" DIM. "C" DIM. "D" DIM. "E"
Required dimensions to
maintain 1/4" min. clearance
from combustible materials 30 1/2" 10 1/2" 6 1/4" 1 1/4" 29 3/4"
Required dimensions to
maintain 1" clearance from
combustible materials 32" 12" 5 1/2" 2" 29"
DIMENSION CHART
DIM. "A" DIM. "B" DIM. "C" DIM. "D" DIM. "E"
Required dimensions to
maintain 1/4" min. clearance
from combustible materials 30 1/2" 10 1/2" 6 1/4" 1 1/4" 29 3/4"
Required dimensions to
maintain 1" clearance from
combustible materials 32" 12" 5 1/2" 2" 29"
DIMENSION CHART
WARNING
•Aminimum of 1/4 inch clearance must be
maintained between the supply air duct and
combustible materials. This is required for
the first 3 feet of ducting.
• It is important to insure that the 1/4 inch minimum
spacing is maintained at all points.
• Failure to do this could result in overheating the
combustible material and may result in fire.
Side section view of supply air duct for
wall mounted unit showing 1/4 inch
clearance to combustible surfaces.

Manual 2100-488
Page 11 of 26
FIGURE5
WALL-MOUNTINGINSTRUCTIONS
FIGURE6
WALL-MOUNTINGINSTRUCTIONS
SEEFIGURE3 — MOUNTINGINSTRUCTIONS
SEE UNIT DIMENSIONS, FIGURE 1,
FOR ACTUAL DIMENSIONS
SEE FIGURE 1 FOR
DUCTDIMENSIONS

Manual 2100-488
Page 12 of 26
FIGURE 7
COMMONWALL-MOUNTINGINSTALLATIONS

Manual 2100-488
Page 13 of 26
WIRING — MAIN POWER
Refer to the unit rating plate for wire sizing information and
maximum fuse or “HACR” type circuit breaker size. Each
outdoor unit is marked with a “Minimum Circuit Ampacity”.
This means that the field wiring used must be sized to carry
that amount of current. Depending on the installed KW of
electric heat, there may be two field power circuits required.
If this is the case, the unit serial plate will so indicate. All
models are suitable only for connection with copper wire.
Each unit and/or wiring diagram will be marked “Use
Copper Conductors Only”. These instructions must be
adhered to. Refer to the National Electrical Code (NEC) for
complete current carrying capacity data on the various
insulation grades of wiring material. All wiring must
conform to NEC and all local codes.
The electrical data lists fuse and wire sizes (75ºC copper)
for all models, including the most commonly used heater
sizes. Also shown are the number of field power circuits
required for the various models with heaters.
The unit rating plate lists a “Maximum Time Delay Relay
Fuse” or “HACR” type circuit breaker that is to be used
with the equipment. The correct size must be used for
proper circuit protection and also to assure that there will
be no nuisance tripping due to the momentary high
starting current of the compressor motor.
The disconnect access door on this unit may be locked to
prevent unauthorized access to the disconnect. To convert
for the locking capability, bend the tab located in the
bottom left hand corner of the disconnect opening under
the disconnect access panel straight out. This tab will now
line up with the slot in the door. When shut, a padlock
may be placed through the hole in the tab preventing entry.
See Start-up section for information on three phase scroll
compressor start-ups.
WIRING — LOW VOLTAGE WIRING
230/208V, 1 phase and 3 phase equipment dual primary
voltage transformers. All equipment leaves the factory
wired on 240V tap. For 208V operation, reconnect from
240V to 208V tap. The acceptable operating voltage
range for the 240 and 208V taps are:
NOTE: The voltage should be measured at the field
power connection point in the unit and while
the unit is operating at full load (maximum
amperage operating condition).
LOW VOLTAGE CONNECTIONS
These units use a grounded 24 volt AC low voltage
circuit.
The “R” terminal is the hot terminal and the “C”
terminal is grounded.
“G” terminal is the fan input.
“Y” terminal is the compressor input.
“B” terminal is the reversing valve input. The reversing
valve must be energized for heating mode.
“R” terminal is 24 VAC hot.
“C” terminal is 24 VAC grounded.
“L” terminal is compressor lockout output. This
terminal is activated on a high or low pressure trip by
the electronic heat pump control. This is a 24 VAC
output.
“W2” terminal is second stage heat (if equipped).
“O1”terminal is the ventilation input. This terminal
energizes any factory installed ventilation option.
“E” terminal is the emergency heat input. This terminal
energizes the emergency heat relay.
“W3” terminal is the dehumidification input. This
terminal energizes compressor, blower and three-way
valve.
NOTE:For total and proper control using DDC, a total
of 7 controlled outputs are required (6 if no
ventilation system is installed). For proper
system operation under Emergency Heat
conditions where the compressor needs to be
deactivated, the B-W2-E outputs need to be
energized. Removing the Y (compressor) signal
alone turns the compressor off, but does not
activate the additional circuitry embedded in the
heat pump for proper and complete operation.
LOWVOLTAGECONNECTIONS
FOR
DDCCONTROL
Fan Only Energize G
Cooling Mode Energize Y, G
Heat Pump Heating Energize Y, G, B
2nd Stg Heating Energize G, W2, Y, B
w/Heat Pump (if employed)
Ventilation Energize G, O1
Emergency Heat Energize B, W2, E, G
Dehumidification Energize W3
paTegnaR
042612-352
802791-022
If the #8403-058 thermostat is used, nine (9) wires should
be run from the thermostat subbase to the 24V terminal
board in the unit. If the #8403-060 thermostat/humidistat
is used, ten (10) wires should be run from the thermostat
subbase to the 24V terminal board. A nine (9) or ten (10)
wire conductor (depending on thermostat used), 18 gauge
copper color-coded thermostat cable is recommended.
The connection points are shown in Figures 8 and 9.

Manual 2100-488
Page 14 of 26
FIGURE 8
WHXXXDX – HOT GAS REHEAT DURING DEHUMIDIFICATION
WITH CS2000A ENERGY MONITOR FULL TIME DEHUMIDIFICATION

Manual 2100-488
Page 15 of 26
FIGURE 9
WHXXXDX–HOTGASREHEATDURINGDEHUMIDIFICATION
WITHPROGRAMMABLETHERMOSTATFULLTIMEDEHUMIDIFICATION
WHXXXDX – HOT GAS REHEAT DURING DEHUMIDIFICATION
WITH CS2000A ENERGY MONITOR AND 8403-060 THERMOSTAT
WITH BUILT IN HUMIDISTAT FULL TIME DEHUMIDIFICATION
IMPORTANT NOTE:
Only the thermostats as shown in Table 4 will work with this equipment. The thermostats must be
matched, and the correct operation can be assured only by proper selection and application of
these parts.

Manual 2100-488
Page 16 of 26
TABLE 4
WALLTHERMOSTATS
tatsomrehTserutaeFtnanimoderP
850-3048 )1511D0225HT(
taeHegats2;looCegats2 elbammargorP-noNcinortcelE revoegnahclaunaMrootuA
060-3048 )544-0211(
taeHegats3;looCegats3 cinortcelEelbammargorP-noN/elbammargorP lanoitnevnoCroPH revoegnahclaunaMrootuA
TABLE 3
THERMOSTATWIRESIZE
remrofsnarT AVALFeguaGeriW
mumixaM ecnatsiD teeFnI
553.2
eguag02 eguag81 eguag61 eguag41 eguag21 5406 001 061 052
IMPORTANT
Only the thermostats shown in this Manual
have been tested with this equipment for
proper operation. Proper unit operation with
thermostats not listed in this Manual cannot be
assured.
You assume responsibility for proper operation
of the unit when using thermostats other than
those listed above.
Temperature and Humidity Controller #8403-060, along with the Outdoor Sensor option Part #8403-061, can be used to:
• Limit minimum outdoor temperature for cooling option.
• Limit minimum outdoor temperature for heat pump option.
• Inhibit electric heat operation for heat pumps above selected outdoor temperature.
Thus, not requiring the optional compressor cut-off thermostat or the electric heat cut-off thermostat option.

Manual 2100-488
Page 17 of 26
START UP
IMPORTANTINSTALLERNOTE
For improved start-up performance, wash the indoor coil
with a dishwashing detergent.
CRANKCASE HEATERS
WH423D units are provided with compressor crankcase
heat. WH484D and WH604D units are not provided
with crankcase heat. These units utilize scroll
compressors which do not require crankcase heat in this
application.
The WH423D models have an insertion well-type heater
located in the lower section of the compressor housing.
This is a self-regulating type heater that draws only
enough power to maintain the compressor at a safe
temperature on these units.
Some form of crankcase heat is essential to prevent
liquid refrigerant from migrating to the compressor,
causing oil pump out on compressor start-up and
possible valve failure due to compressing a liquid.
The decal in Figure 10 is affixed to all WH423D units
detailing start-up procedure. This is very important.
Please read carefully.
HIGH PRESSURE SWITCH
The models are supplied with a remote reset high
pressure switch. If tripped, this pressure switch may be
reset by turning the thermostat off then back on again.
THREE PHASE SCROLL COMPRESSOR
START UP INFORMATION
Scroll compressors, like several other types of
compressors, will only compress in one rotational
direction. Direction of rotation is not an issue with
single phase compressors since they will always start
and run in the proper direction.
However, three phase compressors will rotate in either
direction depending upon phasing of the power. Since
there is a 50-50 chance of connecting power in such a
way as to cause rotation in the reverse direction,
verification of proper rotation must be made. All three
phase scroll units incorporate a phase monitor to ensure
proper field wiring. See the Phase Monitor later in this
manual.
Verification of proper rotation must be made any time a
compressor is change or rewired. If improper rotation is
corrected at this time there will be no negative impact on
the durability of the compressor. However, reverse
operation for over one hour may have a negative impact
on the bearing due to oil pump out.
FIGURE 10
STARTUPLABEL
NOTE:If compressor is allowed to run in reverse
rotation for several minutes, the compressor's
internal protector will trip.
All three phase ZR3 compressors are wired identical
internally. As a result, once the correct phasing is
determined for a specific system or installation,
connecting properly phased power leads to the same
Fusite terminal should maintain proper rotation
direction.
Verification of proper rotation direction is made by
observing that suction pressure drops and discharge
pressure rises when the compressor is energized.
Reverse rotation also results in an elevated sound level
over that with correct rotations, as well as, substantially
reduced current draw compared to tabulated values.
The direction of rotation of the compressor may be
changed by reversing any two line connections to the
unit.
IMPORTANT
THESEPROCEDURES MUSTBEFOLLOWEDAT
INITIALSTARTUPANDATANYTIME POWERHAS
BEEN REMOVED FOR 12 HOURS OR LONGER.
TO PREVENT COMPRESSOR DAMAGE WHICH MAY
RESULT FROM THE PRESENCE OF LIQUID
REFRIGERANT IN THE COMPRESSOR CRANKCASE:
1. MAKECERTAINTHE ROOMTHERMOSTATIS
INTHE“OFF” POSITION.(THECOMPRESSOR
IS NOT TO OPERATE.)
2. APPLY POWER BY CLOSING THE SYSTEM
DISCONNECT SWITCH. THIS ENERGIZES
THE COMPRESSOR HEATER WHICH
EVAPORATESTHE LIQUID REFRIGERANTIN
THE CRANKCASE.
3. ALLOW 4 HOURS OR 60 MINUTES PER
POUND OF REFRIGERANT IN THE SYSTEM
AS NOTED ON THE UNIT RATING PLATE,
WHICHEVER IS GREATER.
4. AFTER PROPER ELAPSED TIME THE
THERMOSTATMAYBE SETTOOPERATETHE
COMPRESSOR.
5. EXCEPTAS REQUIRED FOR SAFETY WHILE
SERVICING, DO NOT OPEN SYSTEM
DISCONNECTSWITCH.
7961-411

Manual 2100-488
Page 18 of 26
PHASE MONITOR
All units with three phase scroll compressors are
equipped with a 3 phase line monitor to prevent
compressor damage due to phase reversal.
The phase monitor in this unit is equipped with two
LEDs. If the Y signal is present at the phase monitor
and phases are correct, the green LED will light. If
phases are reversed, the red fault LED will be lit and
compressor operation is inhibited.
If a fault condition occurs, reverse two of the supply
leads to the unit. Do not reverse any of the unit factory
wires as damage may occur.
SERVICE HINTS
1. Caution owner/operator to maintain clean air filters at
all times. Also, not to needlessly close off supply and
return air registers. This reduces airflow through the
system, which shortens equipment service life as well
as increasing operating costs.
2. Switching to heating cycle at 75°F or higher outside
temperature may cause a nuisance trip of the remote
reset high pressure switch. Turn thermostat off, then
on to reset the high pressure switch.
3. The heat pump wall thermostats perform multiple
functions. Be sure that all function switches are
correctly set for the desired operating mode before
trying to diagnose any reported service problems.
4. Check all power fuses or circuit breakers to be sure
they are the correct rating.
5. Periodic cleaning of the outdoor coil to permit full
and unrestricted airflow circulation is essential.
SEQUENCE OF OPERATION
OCCUPIEDMODE
VENTILATION SEQUENCE – The ERV and indoor
blower will be continuously energized when the A1
terminal is energized.
COOLING SEQUENCE – On a call for cooling, the
compressor of the unit is energized to provide cooling.
A call for cooling cancels dehumidification mode.
Cooling mode is only available when the timer is
energized. See Figure 13.
Circuit R-Y makes at thermostat pulling in compressor
contactor, starting the compressor and outdoor motor.
The G (indoor motor) circuit is automatically completed
on any call for cooling operation or can be energized by
manual fan switch on subbase for constant air
circulation. Refer to Figure 13.
HEATING SEQUENCE – On a call for heating, the
compressor and reversing valve of the unit are
energized to provide heat pump heating. If the room
temperature falls below the 2nd stage heating set point
backup electric heat is energized. Heat pump heating is
only available when the timer is energized. If heating is
energized any call for dehumidification is ignored. If
dehumidification is already energized a call for 2nd
stage heating is needed to cancel dehumidification
mode.
A 24V solenoid coil on reversing valve controls heating
cycle operation. A thermostat demand for heat
completes R-W1 circuit, pulling in compressor
contactor starting compressor and outdoor motor. R-G
also make starting indoor blower motor.
DEHUMIDIFICATION SEQUENCE – On a call for
dehumidification the compressor and three way valve of
the unit are energized to provide dehumidification.
Dehumidification mode will continue until the
humidistat is satisfied. If the room temperature falls
below 1st stage heating setpoint, electric heat will be
energized by the room thermostat and cycle to maintain
room temperature. If 2nd stage heating setpoint is
reached, dehumidification is de-energized and heat
pump heating is energized. A call for cooling cancels
dehumidification mode. Refer to Figure 14.
UNOCCUPIEDMODE
Cooling, heating, emergency heat and ventilation are
inhibited.
DEHUMIDIFICATION SEQUENCE – On a call for
dehumidification the compressor and three way valve of
the unit are energized to provide dehumidification.
Dehumidification mode will continue until the
humidistat is satisfied. If the room temperature falls
below 65 degrees and dehumidification is energized,
electric heat will be energized by the return air
thermostat and cycle to maintain room temperature.
See Figure 14.
OTHERCONTROLSEQUENCE
Any time the indoor coil temperature falls below 32
degrees the compressor will be de-energized until the
coil temperature rises above 57 degrees.
PRESSURE SERVICE PORTS
High and low pressure service ports are installed on all
units so that the system operating pressures can be
observed. Pressure tables can be found later in the
manual covering all models on both cooling and heating
cycles. It is imperative to match the correct pressure
curve to the unit by model number.

Manual 2100-488
Page 19 of 26
DEFROST CYCLE
The defrost cycle is controlled by temperature and time
on the solid state heat pump control. See Figure 11.
When the outdoor temperature is in the lower 40°F
temperature range or colder, the outdoor coil
temperature is 32°F or below. This coil temperature is
sensed by the coil temperature sensor mounted near the
bottom of the outdoor coil. Once coil temperature
reaches 30°F or below, the coil temperature sensor
sends a signal to the control logic of the heat pump
control and the defrost timer will start.
After 60 minutes at 30°F or below, the heat pump
control will place the system in the defrost mode.
During the defrost mode, the refrigerant cycle switches
back to the cooling cycle, the outdoor motor stops,
electric heaters are energized, and hot gas passing
through the outdoor coil melts any accumulated frost.
When the temperature rises to approximately 57°F, the
coil temperature sensor will send a signal to the heat
pump control which will return the system to heating
operations automatically.
If some abnormal or temporary condition such as a high
wind causes the heat pump to have a prolonged defrost
cycle, the heat pump control will restore the system to
heating operation automatically after 10 minutes.
The heat pump defrost control board has an option of
30, 60 or 90-minute setting. All models are shipped
from the factory on the 60-minute pin. If special
circumstances require a change to another time, remove
the wire from the 60-minute terminal and reconnect to
the desired terminal. The manufacturer's
recommendation is for 60-minute defrost cycles. Refer
to Figure 11.
There is a cycle speed up jumper on the control. This
can be used to reduce the time between defrost cycle
operation without waiting for time to elapse.
Use a small screwdriver or other metallic object, or
another 1/4 inch QC, to short between the SPEEDUP
terminals to accelerate the HPC timer and initiate
defrost.
Be careful not to touch any other terminals with the
instrument used to short the SPEEDUP terminals. It
may take up to 10 seconds with the SPEEDUP terminals
shorted for the speedup to be completed and the defrost
cycle to start.
As soon as the defrost cycle kicks in remove the
shorting instrument from the SPEEDUP terminals.
Otherwise the timing will remain accelerated and run
through the 1-minute minimum defrost length sequence
in a matter of seconds and will automatically terminate
the defrost sequence.
There is an initiate defrost jumper (sen jump) on the
control that can be used at any outdoor ambient during
the heating cycle to simulate a 0° coil temperature. This
can be used to check defrost operation of the unit
without waiting for the outdoor ambient to fall into the
defrost region.
By placing a jumper across the SEN JMP terminals (a
1/4 inch QC terminal works best) the defrost sensor
mounted on the outdoor coil is shunted out and will
activate the timing circuit. This permits the defrost
cycle to be checked out in warmer weather conditions
without the outdoor temperature having to fall into the
defrost region.
In order to terminate the defrost test the SEN JMP
jumper must be removed. If left in place too long the
compressor could stop due to the high pressure control
opening because of high pressure condition created by
operating in the cooling mode with outdoor fan off.
Pressure will rise fairly fast as there is likely no actual
frost on the outdoor coil in this artificial test condition.
There is also a 5-minute compressor time delay function
builtinto the HPC. Thisis to protect the compressorfrom
shortcycling conditions. Insome instancesit ishelpful to
the service technician to override or speed up this timing
period,andshortingouttheSPEEDUPterminals
for a few seconds can do this.
FIGURE 11
DEFROSTCONTROLBOARD

Manual 2100-488
Page 20 of 26
TROUBLESHOOTING
TABLE 5
TROUBLESHOOTING
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SOLID STATE HEAT PUMP CONTROL
TROUBLESHOOTING PROCEDURE
1. NOTE: A thorough understanding of the defrost
cycle sequence is essential. Review that section
earlier in this manual prior to troubleshooting the
control. Turn on AC power supply to unit.
2. Turn thermostat blower switch to “fan on” – the
indoor blower should start. (If it doesn’t,
troubleshoot indoor unit and correct problem.)
3. Turn thermostat blower to “auto” position. Indoor
blower should stop. NOTE: Many models have a
1-minute blower time delay on “off” command;
wait for this to time-out.
4. Set system switch to “heat” or “cool”. Adjust
thermostat to call for heat or cool. The indoor
blower, compressor and outdoor fan should start.
NOTE: If there was no power to 24 volt transformer,
the compressor and outdoor fan motor will not start for
5 minutes. This is because of the compressor short
cycle protection.