Bard WH421D Series User manual

WALL MOUNTED
PACKAGE HEAT PUMPS
MODELS:
WH421D
WH483D
WH602D
INSTALLATION INSTRUCTIONS
Manual : 2100-403A
Supersedes: 2100-403
File: Volume III Tab 17
Date: 09-01-03
Bard Manufacturing Company, Inc.
Bryan, Ohio 43506
Since 1914...Moving ahead just as planned.

Contents
Getting Other Informations and Publications
For more information, contact these publishers:...... 1
Wall Mount General Information
Heat Pump Wall Mount Model Nomenclature.......... 2
Shipping Damage .................................................... 5
General ................................................................ 5
Duct Work................................................................ 5
Filters ................................................................ 5
Fresh Air Intake ....................................................... 6
Condensate Drain.................................................... 6
Installation Instructions
Wall Mounting Information....................................... 7
Mounting the Unit .................................................... 7
Typical Installations ................................................. 7
Wiring – Main Power ..............................................11
Wiring – Low Voltage..............................................11
Low Voltage Connections .......................................11
Thermostat Indicator Lamps .................................. 14
Emergency Heat Mode .......................................... 14
Compressor Malfunction Light............................... 14
Start Up
Important Installer Note ......................................... 15
Crankcase Heaters................................................ 15
High Pressure Switch ............................................ 15
Three Phase Scroll Compressor Start Up.............. 15
Phase Monitor ....................................................... 16
Service Hints ......................................................... 16
Sequence of Operation.......................................... 16
Dehumidification .................................................... 16
Pressure Service Ports.......................................... 17
Defrost Cycle ......................................................... 17
Troubleshooting
Solid State Heat Pump Control
Troubleshooting Procedure................................ 19
Checking Temperature Sensor
Outside Unit Circuit............................................ 20
Temperature vs. Resistance of
Temperature Sensor .......................................... 20
Fan Blade Dimensions .......................................... 21
Removal of Fan Shroud......................................... 21
Refrigerant Charge ................................................ 21
Pressure Tables ................................................ 22-23
Optional Accessories ............................................. 23
Figures
Figure 1 Unit Dimensions...................................... 3
Figure 2 Blower Damper Assembly ....................... 6
Figure 3 Mounting Instructions.............................. 8
Figure 4 Electric Heat Clearance .......................... 8
Figure 5 Wall Mounting Instructions...................... 9
Figure 6 Wall Mounting Instructions...................... 9
Figure 7 Common Wall Mounting Installations.... 10
Figure 8 Hot Gas Reheat During
Dehumidification with CS200 ............ 12
Figure 9 Hot Gas Reheat During
Dehumidification with
Programmable Thermostat ................ 13
Figure 10 Start Up Label ....................................... 15
Figure 11 Defrost Control Board ........................... 18
Figure 12 Fan Blade Setting ................................. 21
Tables
Table 1 Electric Heat Table .................................. 2
Table 2 Electrical Specifications .......................... 4
Table 3 Thermostat Wire Size ........................... 14
Table 4 Wall Thermostats .................................. 14
Table 5 Troubleshooting .................................... 19
Table 6 Fan Blade Dimensions.......................... 21
Table 7 Suction Line Temperatures ................... 21
Table 8 Recommended Operating Ranges ....... 21
Table 9 Indoor Blower Performance .................. 21
Table 10 Maximum ESP of Operation.................. 22
Table 11 Pressure Table – Cooling...................... 22
Table 12 Pressure Table – Heating...................... 23
Table 13 Optional Accessories ............................ 23

Manual 2100-403
Page 1
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 2100-403
Page 2
WALL MOUNT GENERAL INFORMATION
Heat Pump Wall Mount Model Nomenclature
WH 48 3 D A 10 X X X X X B
TABLE 1
ELECTRIC HEAT TABLE
sledoMAD124HW BD124HW BD384HWCD124HW AD384HW AD206HW BD384HW BD206HW CD384HW CD206HW
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
(See Chart Below
NOTE: For 0 KW and circuit breakers (230/208 V) or pull disconnects (460 V) applications, insert 0Z in the KW field of model number.
MODEL NUMBER
CAPACITY
42 – 3-1/2 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
3 –Colonial White
4 –Buckeye Gray
FILTER OPTIONS
X – One Inch Throwaway
(Standard)
W – One Inch Washable
P – Two 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 – 6KW
09 – 9 KW
10 – 10 KW
VOLTS & PHASE
A – 230/208/60-1
B – 230/208/60-3
C – 460/60-3
DEHUMIDIFICATION

Manual 2100-403
Page 3
FIGURE 1
UNITDIMENSIONS
MIS-411

Manual 2100-403
Page 4
Maximum size of the time delay fuse or HACR type circuit breaker for protection of field wiring conductors.
Based on 75°C copper wire. All wiring must conform to NEC and all local codes.
Maximum 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.
f
c
d
e
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,00AD124HW 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,00BD124
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,00CD124HW 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,00AD384HW 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,00BD38
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,00CD384HW
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,00AD206HW 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,00BD2
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,00CD206HW
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 2100-403
Page 5
SHIPPING DAMAGE
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 1 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 air flow
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.
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 4
and 5 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.
Any grille that meets the 5/8 inch louver criteria, may be
used. It is recommended that Bard Return Air Grille Kit
RG-2 thru RG-5 or RFG-2 thru 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.
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 2100-403
Page 6
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.
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 1.
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.
MIS-938
FIGURE 2
BLOWERDAMPERASSEMBLY
BLADEISLOCKED
CLOSEDFOR
SHIPPING

Manual 2100-403
Page 7
INSTALLATION INSTRUCTIONS
WALL MOUNTING INFORMATION
1. Two holes, for the supply and return air openings,
must be cut through the wall as shown in Figure 2.
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 4
and 5.
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 30-1/2" x 10-1/2" 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 2, 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 2.
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 6 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 2.
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 2100-403
Page 8
FIGURE 3
MOUNTINGINSTRUCTIONS
WARNING
• A minimum 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.
FIGURE 4
ELECTRICHEAT CLEARANCE
Side section view of supply air
duct for wall mounted unit
showing 1/4 inch clearance to
combustible surfaces.
MIS-277
MIS-796
NOTE: It is recommended that a bead of
silicone caulking be placed behind the
side mounting flanges and under the top
flashing at the time of installation.

Manual 2100-403
Page 9
FIGURE 5
WALL-MOUNTINGINSTRUCTIONS
FIGURE 6
WALL-MOUNTINGINSTRUCTIONS
MIS-548
MIS-549
SEE FIGURE 3 — MOUNTING INSTRUCTIONS
SEE UNIT DIMENSIONS, FIGURE 1,
FOR ACTUAL DIMENSIONS
SEE FIGURE 1 FOR
DUCT DIMENSIONS

Manual 2100-403
Page 10
FIGURE 7
COMMONWALL-MOUNTINGINSTALLATIONS
MIS-550

Manual 2100-403
Page 11
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:
Nine (9) wires should be run from thermostat subbase to
the 24V terminal board in the unit. A nine conductor, 18
gauge copper, color-coded thermostat cable is
recommended. The connection points are shown in
Figures 7 and 8.
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 for cooling.
"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).
"01" 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 24 dehumidification circuit.
"W1" terminal is the compressor input of heat pump
heating.
NOTE: for total and proper control using DDC, a
total of 8 controlled outputs are required (7 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 W1 (compressor)
signal alone turns the compressor off, but does
not activate the additional circuitry embedded
in the heat pump for proper and complete
operation.
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).
paTegnaR
042 802 612-352 781-022
SNOITCENNOCEGATLOVWOL LORTNOCCDDROF
ylnOnaFGezigrenE
edoMgnilooCG,YezigrenE
gnitaeHpmuPtaeHB,G,1WezigrenE
gnitaeHegatSdn2 )deyolpmefi( B,1W,2W,GezigrenE
noitalitneV1O,GezigrenE
noitacifidimuheD3WezigrenE
taeHycnegremEG,E,2W,BezigrenE

Manual 2100-403
Page 12
FIGURE 8
WHXXXDX – HOT GAS REHEAT DURING DEHUMIDIFICATION
WITH CS2000 ENERGY MONITOR FULL TIME DEHUMIDIFICATION
IMPORTANT NOTE:
Only the thermostat and subbase combinations as shown in Table 4 will work with this
equipment. The thermostat and subbase must be matched and the correct operation can
be assured only by proper selection and application of these parts.
MIS-1561
NC
C
CRNCC
AREA
OCCUPIED
PWR HVAC
H600A
6543
CG RY1 BW1 W2 EL
CGRDH Y1 YB
W1 W2 W3 EL01
FACTORYJUMPER
8403-032
BARD CS2000
8403-038
HONEYWELLH600A
HUMIDITY CONTROLLER
OR
8403-047
DEHUMIDISTAT
VICONICS
H200-10-21-10
8403-042
HONEYWELL
T8511G1070
THERMOSTAT
UNIT LOW VOLTAGE
TERMINAL BLOCK

Manual 2100-403
Page 13
FIGURE 9
WHXXXDX – HOT GAS REHEAT DURING DEHUMIDIFICATION
WITH PROGRAMMABLE THERMOSTAT FULL TIME DEHUMIDIFICATION
IMPORTANT NOTE:
Only the thermostat and subbase combinations as shown in Table 4 will work with this
equipment. The thermostat and subbase must be matched, and the correct operation can
be assured only be proper selection and application of these parts.
MIS-1562A
8403-038 HONEYWELL H600A
HUMIDITY CONTROLLER
OR
8403-047 DEHUMIDISTAT
VICONICS H200-10-21-10
8403-049 WHITE-RODGERS
IF93-380 THERMOSTAT
UNIT LOW VOLTAGE
TERMINAL BLOCK
H600A
FACTORY JUMPER

Manual 2100-403
Page 14
THERMOSTAT INDICATOR LAMPS
The red lamp will come on if there is any problem that
prevents the compressor from running when it is
supposed to be.
EMERGENCY HEAT MODE
The operator of the equipment must manually place the
system switch in this position. This is done when there
is a known problem with the unit, or when the red lamp
comes on indicating a problem.
COMPRESSOR MALFUNCTION LIGHT
Actuation of the red lamp is accomplished by a relay
output from the heat pump control board which is
factory installed. Any condition such as loss of charge,
high head pressure, etc., that will prevent compressor for
operating will cause red lamp to activate. This is a
signal to the operator of the equipment to place system
in emergency heat position.
TABLE 3
THERMOSTAT WIRE SIZE
remrofsnarT AVALFeguaGeriW
mumixaM ecnatsiD teeFnI
553.2
eguag02 eguag81 eguag61 eguag41 eguag21 5406 001 061 052
TABLE 4
WALLTHERMOSTATS
tatsomrehTserutaeFtnanimoderP
240-3048 )0701G1158T(
taehegats2;loocegats1 elbammargorP-noNcinortcelE revoegnahclaunaMrootuA
940-3048 083-39F1
taehegats3;loocegats2 elbammargorPyaD7 revoegnahClaunaMrootuA

Manual 2100-403
Page 15
START UP
IMPORTANT INSTALLER NOTE
For improved start-up performance, wash the indoor coil
with a dishwashing detergent.
CRANKCASE HEATERS
WH421 units are provided with compressor crankcase
heat. WH483 and WH602 units are not provided with
crankcase heat. These units utilize scroll compressors
which do not require crankcase heat in this application.
The WH421 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 9 is affixed to all WH421 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" on page 15
of 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
START UP LABEL
IMPORTANT
THESE PROCEDURES MUST BE FOL-
LOWEDATINITIALSTARTUPANDATANY
TIMEPOWER HASBEEN REMOVED FOR
12 HOURS OR LONGER.
TO PREVENT COMPRESSOR DAMAGE
WHICH MAY RESULT FROM THE PRESENCE
OF LIQUID REFRIGERANT INTHE COMPRES-
SOR CRANKCASE:
1. MAKE CERTAIN THE ROOM THERMOSTAT IS
IN THE “OFF“ POSITION. (THE COMPRESSOR
IS NOT TO OPERATE.)
2. APPLY POWER BY CLOSING THE SYSTEM
DISCONNECTSWITCH.THISENERGIZESTHE
COMPRESSOR HEATER WHICH EVAPO-
RATES THE LIQUID REFRIGERANT IN THE
CRANKCASE.
3. ALLOW 4 HOURS OR 60 MINUTES PER
POUNDOF REFRIGERANTINTHESYSTEMAS
NOTEDONTHEUNITRATINGPLATE, WHICH-
EVER IS GREATER.
4. AFTER PROPER ELAPSED TIME THE THER-
MOSTATMAYBE SETTOOPERATETHECOM-
PRESSOR.
5. EXCEPT AS REQUIRED FOR SAFETY WHILE
SERVICING,DO NOTOPENSYSTEM DISCON-
NECT SWITCH.
7961-411
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.

Manual 2100-403
Page 16
SEQUENCE OF OPERATION
COOLING – 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.
HEATING – A 24V solenoid coil on reversing valve
controls heating cycle operation. Two thermostat
options, one allowing "Auto" changeover from cycle to
cycle and the other constantly energizing solenoid coil
during heating season, and thus eliminating pressure
equalization noise except during defrost, are to be used.
On "Auto" option a circuit is completed from R-W1 and
R-Y on each heating "on" cycle, energizing reversing
valve solenoid and pulling in compressor contactor
starting compressor and outdoor motor. R-G also make
starting indoor blower motor. Heat pump heating cycle
now in operation. The second option has no "Auto"
changeover position, but instead energizes the reversing
valve solenoid constantly whenever the system switch
on subbase is placed in "Heat" position, the "B"
terminal being constantly energized from R. A
Thermostat demand for heat completes r-Y circuit,
pulling in compressor contactor starting compressor and
outdoor motor. R-G also make starting indoor blower
motor.
DEHUMIDIFICATION
OCCUPIED MODE
VENTILATION SEQUENCE – The ERV and indoor
blower will be continuously energized when the timer 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.
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.
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.
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.
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 homeowner to maintain clean air filters at all
times. Also, not to needlessly close off supply and
return air registers. This reduces air flow 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.

Manual 2100-403
Page 17
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.
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 minutes 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,andshortingouttheSPEEDUPterminalsforafew
seconds can do this.

Manual 2100-403
Page 18
FIGURE 11
DEFROSTCONTROLBOARD