Armstrong Air Conditioning 4HP13 Installation manual

Page 1 of 17506318-01 Issue 0946
INSTALLATION / START-UP INSTRUCTIONS
4HP13/14 SPLIT SYSTEM HEAT PUMP
HOMEOWNERS INFORMATION MANUAL
WARNING
Installation or repairs made by unqualified persons can result in hazards to you and others. Installation
MUST conform with local building codes and with the National Electrical Code NFPA 70/ANSI C1-1993 or
current edition and Canadian Electrical Code Part 1 CSA C22.1.
These instructions must be read and understood completely before attempting installation.
SAFETY PRECAUTIONS .....................................................................2
UNIT LOCATION & INSTALLATION .....................................................2
ROOFTOP INSTALLATION & RECOMMENDATIONS ........................3
CLEARANCE REQUIREMENTS ..........................................................3
REFRIGERATION LINE SETS .............................................................3
INSTALLATION OF LINE SETS............................................................4
LEAK CHECK ....................................................................................... 4
EVACUATING & CHARGING................................................................4
OPENING SERVICE VALVE .................................................................4
ELECTRICAL CONNECTIONS............................................................ 5
CONTROL WIRING.............................................................................. 5
START-UP PROCEDURE .................................................................... 6
ADJUSTING CHARGE......................................................................... 6
SYSTEM OPERATIONS ...................................................................... 7
DEFROST SYSTEM (Time -Temp) ...................................................... 7
DEFROST SYSTEM (Demand Defrost) .............................................. 8
SINGLE PHASE WIRING DIAGRAM (13 SEER).............................. 14
SINGLE PHASE WIRING DIAGRAM (14 SEER)...............................15
HOMEOWNER’S INFORMATION ..................................................... 16
Improper installation, adjustment, alteration, service or maintenance will void the warranty. The qualified installer or
agencymustusefactory-authorizedkits or accessories when added to this products. Refertotheindividualinstructions
included with the specific accessory kit.
CAUTION
NOTE
These instructions are intended as a general guide and do not supersede national, state or local codes in any way.
These instructions must be left with the property owner.
These units are designed for use in residential and light commercial type buildings. Heat Pumps may
onlybe installedwith indoorcombinations listed in theAir-Conditioning,Heating and RefrigerationInstitute
(AHRI) Directory of Certified Products.
Inspect the unit for any damage before installation. If damage is found, notify the transportation company
immediately and file a concealed damage claim.
TABLE OF CONTENTS

506318-01Page 2 of 17 Issue 0946
NOTE TO INSTALLING DEALER
Theseinstructions and warrantyareto begivento the owner
or displayed near the indoor air handler unit.
gas to LP gas.
WARNING
Thisproductand/ortheindoor unit that is matched with
may contain fiberglass wool.
Disturbing the insulation during installation,
maintenance,or repairwillexpose youtofiberglasswool
dust. (Fiberglasswool isknownto theStateof California
to cause cancer.)
Fiberglass wool may also cause respiratory, skin, and
eye irritation.
To reduce exposure to this substance or for further
information, consult material safety data sheets
available from your distributor.
Before installing, modifying, or servicing system, main
electricaldisconnect switchmustbe intheOFF position.
There may be more than 1 disconnect switch. Lock
out and tag switch with a suitable warning label.
Electrical shock can cause personal injury or death.
WARNING
Safety Precautions
Follow all safety codes. Wear safety glasses and work
gloves. Use quenching cloth for brazing operations. Have
fire extinguisher available. Read these instructions
thoroughly and follow all warning or cautions attached to
the unit.
1. Alwayswear proper personalprotectionequipment.
2. Alwaysdisconnect electricalpowerbefore removing
panel or servicing equipment.
3. Keep hands and clothing away from moving parts.
4. Handle refrigerant with caution, refer to proper
MSDS from refrigerant supplier.
5. Use care when lifting, avoid contact with sharp
edges.
UNIT LOCATION & INSTALLATION
NOTE: In some cases noise in the living area has been
traced to gas pulsations from improper installation of
equipment.
1. Locate unit away form windows, patios, decks, etc.
where unit operation sounds may disturb customer.
2. Ensure that vapor and liquid tube diameters are
appropriate to capacity of unit.
3. Runrefrigerant tubes asdirectlyaspossible by avoiding
unnecessary turns and bends.
4. Leavesome slack between structure and unit to absorb
vibration.
5. When passing refrigerant tubes through the wall, seal
opening with RTV or other silicon-based caulk.
6. Avoid direct tubing contact with water pipes, duct work,
floor joists, wall studs, floors, walls, and any structure.
7. Do not suspend refrigerant tubing from joists and studs
with a rigid wire or strap which comes in direct contact with
tubing.
8. Ensure that tubing insulation is pliable and completely
surrounds vapor tube.
When outdoor unit is connected to factory-approved
indoorunit,outdoorunit contains system refrigerant charge
for operation with indoor unit of the same size when
connected by 15 ft. of field-supplied tubing. For proper unit
operation, check refrigerant charge using charging
information located on control box cover.
IMPORTANT: Maximum liquid-line size is 3/8 in. O.D.
for all residential applications including
long lines.
Outdoor Section
Zoning ordinances may govern the minimum distance
the condensing unit can be installed from the property line.
Install on a Solid, Level Mounting Pad
The outdoor section is to be installed on a solid
foundation. This foundation should extend a minimum of
2" (inches) beyond the sides of the outdoor section. To
reduce the possibility of noise transmission, the foundation
slab should NOT be in contact with or be an integral part of
the building foundation.

Page 3 of 17506318-01 Issue 0946
Elevate Unit
CAUTION
Accumulation of water and ice in base pan may cause
equipment damage.
Elevateunit per local climate and code requirementsto
provide clearance above estimated snowfall level and
ensureadequatedrainageof unit. Use snow standin areas
where prolonged freezing temperatures are encountered.
If conditions or local codes require the unit be attached
to pad or mounting frame, tie down bolts should be used
andfastenedthrough knockoutsprovided in unit base pan.
Roof Top Installations
Mount on level platform or frame 6 inches above roof
surface. Place unit above a load-bearing wall and isolate
unit and tubing set from structure. Arrange supporting
members to adequately support unit and minimize
transmission of vibration to building. Ensure roof structure
and anchoring method is adequate for location. Consult
local codes governing rooftop applications.
Roofmounted unitsexposed to windsabove 5 mphmay
require wind baffles to achieve adequate defrost. A sheet
metal baffle should be spaced 6-1/2" from the fall of the
coil. The height should cover the face of the coil and the
length should be 6" from the access panel.
NOTE: Unit must be level to within ± 2 (± 3/8 in./ft) per
compressor manufacturer specifications.
Clearance Requirements
When installing, allow sufficient space for airflow
clearance,wiring, refrigerant piping,and service. For proper
airflow, quiet operation and maximum efficiency. Position
so water, snow, or ice from roof or eaves cannot fall directly
on unit.
DO LOCATE THE UNIT:
!With proper clearances on sides and top of unit
!On a solid, level foundation or pad
!To minimize refrigerant line lengths
DO NOT LOCATE THE UNIT:
!On brick, concrete blocks or unstable surfaces
!Near clothes dryer exhaust vents
!Near sleeping area or near windows
!Under eaves where water, snow or ice can fall
directly on the unit
!with clearance less than 2 ft. from a second unit
!with clearance less than 4 ft. on top of unit
OperatingAmbient
The minimum outdoor operating ambient in cooling
modeis55°F, and the maximum outdoor operatingambient
in cooling mode is 125°F. The maximum outdoor operating
ambient in heating mode is 66°F.
Refrigeration Line Sets
Useonlyrefrigerant grade copper tubes. Splitsystems
may be installed with up to 50 feet of line set (no more than
20feet vertical) without special consideration (see long line
set guidelines).
Itisimportantthat no tubing be cut or seals broken until
youare readyto actuallymake connectionsto theevaporator
andto thecondenser section. DONOTremove rubberplugs
or copper caps from the tube ends until ready to make
connections at evaporator and condenser. Under no
circumstances leave the lines open to the atmosphere for
any period of time, if so unit requires additional evacuation
to remove moisture.
Be extra careful with sharp bends. Tubing can “kink”
very easily, and if this occurs, the entire tube length will
have to be replaced. Extra care at this time will eliminate
future service problems.
It is recommended that vertical suction risers not be
up-sized. Proper oil return to the compressor should be
maintained with suction gas velocity.
Recommended Liquid & Vapor Tube Diameters (In.)
Unit
Size
LIQUID VAPOR
Connections Dia. Connections Dia.Tube Dia. Tube Dia.
018
024
030
036
042
048
060
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
3/4”
3/4”
3/4”
3/4”
3/4”
3/4”
*1-1/8
7/8”
7/8”
7/8”
7/8”
7/8”
7/8”
7/8”
* FIELD SUPPLIED 7/8 X 1-1/8 CONNECTOR REQUIRED ON BOTH ENDS OF VAPOR TUBING.

506318-01Page 4 of 17 Issue 0946
Installation of Line Sets
DO NOT fasten liquid or suction lines in direct contact
withthe floor or ceilingjoist. Usean insulated or suspension
type of hanger. Keep both lines separate, and always
insulate the suction line. Long liquid line runs (30 feet or
more) in an attic will require insulation. Route refrigeration
line sets to minimize length.
DONOTlet refrigerant lines come in direct contactwith
foundation. When running refrigerant lines through the
foundation or wall, openings should allow for a sound and
vibration absorbing material to be placed or installed
between tubing and foundation. Any gap between
foundation or wall and refrigerant lines should be filled with
a vibration damping material.
CAUTION
IfANYrefrigeranttubing isburied,provide a6 inch vertical
rise at service valve. Refrigerant tubing lengths up to 36
inches may be buried without further special
consideration. Forlengths above 36 inches, consultyour
local distributor.
Beforemaking braze connections, be sure all jointsare
clean. Beforeheat isappliedfor brazing,drynitrogen should
beflowingthroughthe tubing to prevent oxidation and scale
formation on the inside of the tubing.
The following is the recommended method for making
braze connections at the refrigerant line connections:
1. Debur and clean refrigerant tube end with emery
cloth or steel brush.
2. Insert tubing into swage fitting connection.
3. Wrap wet rags over valves to protect from heat.
4. Allow dry nitrogen to flow through refrigerant lines.
5. Brazejoint, using a suitablebrazing alloy forcopper
to copper joints.
6. Quench the joint and tubing with water using a wet
rag. Leaverag on fitting body andre-wetwith water
to help cool area.
Leak Check
Refrigeration lines and indoor coil must be checked for
leaks after brazing and before evacuation. The
recommendedprocedure is toapply a traceamountof vapor
refrigerant (approximately two ounces or 3 psig) into the
line set and indoor coil, then pressurize with 150 psig of dry
nitrogen. Use a refrigerant leak detector to check all joints.
The system may also be checked for leaks using a halide
torch or pressure and soapy solution. After completion of
leak check, relieve all pressure from system before
evacuation.
Evacuating And Charging Instructions
NOTE: Intentional release of CFC or HCFC refrigerant
to the atmosphere violates Federal Law. It may also
violate State and Local Codes. Check all Federal, State
and Local Codes before proceeding.
Theseoutdoorunits are pre-charged at the factory with
adequaterefrigerant to handle 15 feet of refrigerant tubing.
NOTE: DO NOT use any portion of the charge for purging
or leak testing. It is mandatory that a thorough evacuation
of the refrigeration lines and indoor coil be performed.
Theliquidline and suction line service valveshavebeen
closed after final testing at the factory. DO NOT disturb
these valves until the lines have been leak checked and
evacuated or the charge in the unit may be lost.
1. Connect the vacuum pump to the center hose of the
manifoldgaugeset,the low-pressure manifold gauge to the
vapor service valve and the high pressure manifold gauge
to the liquid service valve.
NOTE: Unnecessary switching of hoses can be avoided
and complete evacuation of all lines can be achieved by
also connecting a branch hose from the manifold gauge
centerport to a cylinder of the proper refrigerant. Provide a
separate shut-off valve to vacuum pump to avoid
contaminating vacuum pump oil with refrigerant.
2. The valves should be kept in the “front seated”
(closed) position. This will allow evacuation of the
refrigerationlinesand the indoor coil, without disturbing the
factory charge in the outdoor unit.
3. Follow the vacuum pump manufacturer’s
instructions. Allow the pump to operate until the system
has been evacuated down to 300 microns. Allow the pump
to continue running for an additional 15 minutes. Turn OFF
the pump and leave the connections secured to the two (2)
service valves. After 5 minutes, if the system fails to hold
500 microns or less, check all connections for tight fit and
repeat the evacuation procedure.
4. Isolate the vacuum pump from the system by
closing the shutoff valves on the gauge-set. Disconnect
the vacuum pump.
Opening Service Valves
After evacuation of the connecting lines, remove the
service valve cap and fully insert the hex wrench into the
stem. A back-up wrench is required on the valve body to
open the valve stem. Back-out counterclockwise until the
valve stem just touches the coined edge.
Wrench sizes:
3/8 service valve: 3/16" Hex wrench
3/4 service valve: 5/16" Hex wrench
7/8 service valve: 5/16" Hex wrench

Page 5 of 17506318-01 Issue 0946
Replace service valve cap and torque to 8-11 ft-lb on 3/
8" valves; 12-15 ft-lb on 3/4" valves; 15-20 ft-lb on 7/8"
valves. Use backup wrench on valve body when torqueing
valve cap.
Install ElectricalAccessories
Refer to the instructions packaged with the accessories.
Electrical Connections
Be sure to check all local codes to determine that the
unitis installedaccordance withlocalrequirements. Consult
the National Electric Code for wire size requirements. Use
60 C wire or higher. Always provide ground connections to
the outdoor unit. Power supply must agree with rating on
unit nameplate.
Providelinevoltage power supply tounitfroma properly
sized disconnect switch. Route power and ground wires
from disconnect switch to unit. Line voltage connections
are made at the line side of the contactor in the control box
of the outdoor unit. Follow the appropriate wiring diagram
attached to inside of the access panel.
Propercircuit protectionrecommendationsare indicated
on Unit Rating Plate. Time delay fuses are required to
prevent blowing due to starting current (the current in rush
when equipment starts is referred to as the Locked Rotor
Amps or (LRA). A fuse of this kind properly sized will give
maximum equipment protection.
Use copper wire only between disconnect switch and
unit.
Remove access panel to gain access to unit wiring.
Extend wires from disconnect through power wiring hole
provided and into unit control box. Flexible conduit is
required for the swing out control box feature.
WARNING
ELECTRICAL SHOCK HAZARD!
Turn OFF electric power before connecting unit,
performinganymaintenanceor removingpanels ordoors.
More than one disconnect may be required to turn off all
power.
FAILURE TO DO SO COULD RESULT IN BODILY
INJURY OR DEATH.
WARNING
Theunit cabinetmust haveanuninterrupted orunbroken
ground to minimize personal injury if an electrical fault
shouldoccur. The ground may consist of electrical wire
or metal conduit when installed in accordance with
existing electrical codes. Failure to follow this warning
can result in an electric shock, fire, or death.
Connectgroundwire to ground connection incontrolbox
for safety. Connect power wiring to contactor.
High voltage power connections to 3-phase models is
madeto “PigTail”leads withfieldsupplied spliceconnectors.
Control Wiring
The control voltage is 24 Vac. NEC Class I insulated 18
AWG is required for control wiring. For lengths longer than
150 feet, contact your local distributor for technical service.
Ensure the room thermostat is properly installed per
instructions shipped with room thermostat. Generally the
thermostat should not be exposed to sunlight, drafts or
vibration and should not be mounted on exterior walls.
Lowvoltagecontrol wire connections should be made to
thescrew connection terminalboardmounted on thedefrost
control as shown. All low voltage control wiring must be
separated from incoming power leads.

506318-01Page 6 of 17 Issue 0946
Heat Pump Application with Electric Heat
Emergency Heat (heating heat pump)
If selector switch on thermostat is set to the emergency
heatposition, the heatpumpwill be lockedoutof the heating
circuit,and all heating will be electric heat ( if applicable). A
jumper should be placed between W and E on the
thermostat so that the electric heat control will transfer to
the first stage heat on the thermostat. This will allow the
indoorblowertocycleonandoff with the electric heatwhen
the fan switch is in the AUTO position.
* Add Jumper on Subbase (Optional)
Start-Up Procedure
1. Check to ensure:
!Service valve and gage port caps are installed and
tightened.
!Voltage supply at unit agrees with nameplate rating.
!Field wiring connections are tight and factory wiring
has not been disturbed and are tight.
!Indoor fan motor is on correct speed tap.
2. Set thermostat selector switch to OFF and fan control
switch to “Auto” is so equipped.
3. Close electrical disconnects to energize system.
4. Set room thermostat at desired temperature. Be sure
set point is below indoor ambient temperature.
5. Set the system switch of the thermostat on COOL (or
HEAT if applicable) and fan switch for continuous
operation (ON) or AUTO, as desired. There will be a 5
minuteshort cyclecompressordelay on startup. Operate
unitfor15-20 minutes, then check the system refrigerant
charge.
6. Adjustrefrigerant charge per “Adjusting Charge”section.
Adjusting Charge
Factory charge is shown on the rating label located on
the access panel.
All split system heat pumps are factory charged
for 15 feet of connecting line set and matched indoor
fan coil. Nameplate refrigerant charge should initially be
adjusted for line set lengths other than 15 feet. For line
sets shorter than 15 feet in length, remove charge. For line
setslonger than 15 feet, addcharge. Oilchargeis sufficient
for all line lengths.
Beforefinaladjustment is made to therefrigerantcharge,
it is imperative that proper indoor airflow be established.
Airflow will be higher across a dry coil versus a wet coil.
Blower charts are calculated with a dry or wet coil basis.
Recommended airflow is 350-450 CFM per ton (12,000
Btuh) through a wet coil. Refer to indoor unit instructions
formethods of determiningairflow andblowerperformance.
All heat pump units are only rated with TXV installed on
indoor coil.
The optimum method for checking the charge is by
weight. However the following methods may be used
to confirm the proper charge:
Cooling Mode:
1. Operate unit a minimum of 10 minutes before
checking charge.
2. Measure liquid service valve pressure by attaching
an accurate gage to service port. Determine
saturation temp. from T/P chart.
3. Measure liquid line temperature by attaching an
accurate thermistor type or electronic thermometer
to liquid line near outdoor coil.
4. Calculate subcooling (saturation temp. measured
temp.) and compare with table on back of central
box cover.
5. Add refrigerant if subcooling is lower than table.
Recover refrigerant if subcooling is high.
6. If ambient temp is lower than 60°F, check charge in
heating mode or weigh refrigerant according to
name plate data.
Heating Mode:
Check charge in heating mode if ambient temp is below
60° F. Indoor temp must be between 65° and 75° F.
Follow steps (1) to (6) above and compare with heating
mode subcooling range on the table on back of central box
cover.
Charge must be rechecked again during the cooling
season.
Cold Weather Application
A cold weather accessory kit may be required for heat
pumps operating at ambient conditions below 25°F.
Supplemental heat should be provided for these conditions
due to the expected performance degeneration.
Refrigeration Charge Adjustment
Liquid Line Diameter Oz. Per Linear Foot *
3/8” .6
* Factory charge for series is for 15’ (ft.) line sets
and matched fan coil.

Page 7 of 17506318-01 Issue 0946
SYSTEM OPERATION
The outdoor unit and indoor blower cycle on demand
from the room thermostat. When the thermostat blower
switch is in the ON position, the indoor blower operates
continuously.
Filter Drier
The outdoor unit is equipped with a bi-flow filter drier. If
replacementisnecessary, order new dryer according to the
service parts manual.
Emergency Heat Function (Room Thermostat)
Anemergencyheatfunction is designed into some room
thermostats. This feature is applicable when isolation of
outdoor unit is required or when auxiliary electric heat is
stagedby outdoor thermostats. Whenthe room thermostat
is placed in the emergency heat position, the outdoor unit
controlcircuitisisolated frompower andfield-provided relays
bypass the outdoor thermostats. An amber indicating light
simultaneouslycomes on to remind the homeowner that he
is operating in the emergency heat mode.
Emergency heat is usually used during an outdoor unit
shutdown, but it should also be used following a power
outage. If power has been off for over an hour and the
outdoor temperature is below 50°F (10°C). System should
be left in the emergency heat mode at least six hours to
allow the crankcase heater sufficient time to prevent
compressor slugging. This applies only to systems with
crank case heaters.
Defrost System Time-Temp
The defrost system includes two (2) components: a
defrost thermostat and a defrost control.
Defrost Thermostat
The defrost thermostat is located on the outdoor coil of
most models and on the liquid line between the check/
expansion valve and the distributor on R-4110A TXV
equipped models. When defrost thermostat senses 29°F
(42 on R-410A TXV’s) or cooler, the thermostat contacts
close and send a signal to the defrost control board to start
thedefrosttiming. Italsoterminatesdefrost when the liquid
line warms up to 60°F.
Defrost Control
The defrost control board includes the combined
functionsof a time/temperaturedefrost control, defrostrelay,
diagnostic LEDs and terminal strip for field wiring
connections.
The control provides automatic switching from normal
heating operation to defrost mode and back. During
compressorcycle, thecontrol accumulates compressor run
times at 30-, 60-, or 90-minute field-adjustable intervals. If
the defrost thermostat is closed when the selected
compressor run time interval ends (call for defrost), the
defrost relay is energized and defrost begins. The factory
settingis 60minutes. However,iffrostaccumulation iseasily
cleared, the optimum efficiency setting is 90 minutes.
Outdoor Unit Defrost Control Board
Defrost Control Timing Pins
Each timing pin selection provides a different
accumulated compressor run time period for one defrost
cycle. This time period must occur before a defrost cycle is
initiated. The defrost interval can be adjusted to 30 (/T1),
60 (T2), or 90 (T3) minutes. The defrost timing jumper is
factory-installed to provided a 90-minute defrost interval. If
thetimingselector jumper is not in placethecontroldefaults
toa 90-minute defrostinterval. Themaximum defrostperiod
is 14 minutes and cannot be adjusted.
ATESToption isprovidedfor troubleshooting. The TEST
mode may be started any time the unit is in the heating
mode and the defrost thermostat is closed or jumpered.
Ifthejumper is in theTEST position atpower-up,thecontrol
will ignore the test pins. When the jumper is placed across
theTESTpinsfor2 seconds,thecontrol willenterthe defrost
mode. If the jumper is removed before an additional 5
second period has elapsed (7 seconds total), the unit will
remain in defrost mode until the defrost thermostat opens
or 14 minutes have passed. If the jumper is not removed
until after the additional 5 second period has elapsed, the
defrost will terminate and the test option will not function
again until the jumper is removed and re-applied.

506318-01Page 8 of 17 Issue 0946
Compressor Delay
The defrost board has a field-selectable function to
reduce occasional sounds that may occur while the unit is
cycling in and out of the defrost mode. The compressor will
becycled“off” for 30 seconds going inandoutofthedefrost
mode when the compressor delay jumper is removed.
NOTE: The 30 second “off” cycle is not functional when
jumpering the TEST pins.
Time Delay
The timed-off delay is 5 minutes long. The delay help to
protectthecompressor from short-cycling in casethepower
to the unit is interrupted or a pressure switch opens. The
delayisbypassedby placing the timer select jumper across
the TEST pins for 0.5 seconds.
Pressure Switch Circuit
The defrost control incorporates 2 pressure switch
circuits. The optional high pressure switch connects to the
boards HI PS terminals. The low pressure switch is factory
installed.
During a single demand cycle, the defrost control will
lock out the unit after the fifth time that the circuit is
interruptedby anypressure switchwiredto thecontrolboard.
In addition, the diagnostic LEDs will indicate a locked-out
pressure switch after the fifth occurrence of an open
pressureswitch. The unit will remain locked out until power
to the board is interrupted, then re-established or until the
jumper is applied to the TEST pins for 0.5 seconds.
NOTE: The defrost control board ignores input from the
low-pressure switch terminals as follows:
!During the TEST mode,
!During the defrost cycle,
!During the 90 second start-up period,
!and for the first 90 seconds each time the reversing
valve switches heat/cool modes. If the TEST pins
are jumpered and the 5 minute delay is being by-
passed, the LO PS terminal signal is not ignored
during the 90 second start-up period.
DEMAND DEFROST SYSTEM DESCRIPTION
The demand defrost controller measures differential
temperaturesto detectwhen thesystemisperformingpoorly
because of ice build-up on the outdoor coil. The controller
“self-calibrates” when the defrost system starts and after
each system defrost cycle. The defrost control board
components are shown below.
The control monitors ambient temperature, outdoor coil
temperature,andtotal run time todeterminewhenadefrost
cycle is required. The coil temperature probe is designed
witha spring cliptoallow mounting to theoutsidecoil tubing.
Thelocation of the coilsensoris importantfor proper defrost
operation.
NOTE - The demand defrost board accurately measures
the performance of the system as frost accumulates
on the outdoor coil. This typically will translate into
longer running time between defrost cycles as more
frost accumulates on the outdoor coil before the board
initiates defrost cycles.
DIAGNOSTIC LEDS
The state (Off, On, Flashing) of two LEDs on the defrost
board (DS1 [Red] and DS2 [Green]) indicate diagnostics
conditions that are described in table.
Mode Green Led (DS2) Red Led (DS1)
OFF
OFF
No power to control
Normal operation/
power to control
Anti-short cycle
lockout
Simultaneous Slow Flash
Alternating Slow Flash
Low pressure switch
fault (Optional)
Low pressure switch
lockout (Optional)
High presssure switch
fault (Optional)
High pressure switch
lockout (Optional)
OFF
OFF
OFF OFF
OFF
ON
Slow FLASH
Slow FLASH

Page 9 of 17506318-01 Issue 0946
DEFROST BOARD PRESSURE SWITCH
CONNECTIONS
The unit’s automatic reset pressure switches (LO PS -
S87andHIPS - S4) are factory-wired into the defrost board
on the LO-PS and HI-PS terminals, respectively.
(OPTIONAL) Low Pressure Switch (LO-PS) — When the
lowpressure switch trips,the defrost board will cycle offthe
compressor, and the strike counter in the board will count
one strike. The low pressure switch is ignored under the
following conditions:
!during the defrost cycle and 90 seconds after the
termination of defrost
!whenthe average ambient sensortemperatureisbelow
15° F (-9°C)
!for 90 seconds following the start up of the compressor
!during “test” mode
High Pressure Switch (HI-PS) — When the high pressure
switch trips, the defrost board will cycle off the compressor,
and the strike counter in the board will count one strike.
DEFROST BOARD PRESSURE SWITCH SETTINGS
High Pressure (auto reset) - trip at 590 psig; reset at 418.
Low Pressure (auto reset) - trip at 25 psig; reset at 40.
5-STRIKE LOCKOUT FEATURE
Theinternal controllogicof theboard countsthe pressure
switch trips only while the Y1 (Input) line is active. If a
pressure switch opens and closes four times during a Y1
(Input), the control logic will reset the pressure switch trip
counter to zero at the end of the Y1 (Input). If the pressure
switch opens for a fifth time during the current Y1 (Input),
the control will enter a lockout condition.
The 5-strike pressure switch lockout condition can be
reset by cycling OFF the 24-volt power to the control board
or by shorting theTEST pins between 1 and 2 seconds. All
timer functions (run times) will also be reset.
If a pressure switch opens while the Y1 Out line is
engaged, a 5-minute short cycle will occur after the switch
closes.
DEFROST SYSTEM SENSORS
Sensors connect to the defrost board through a field–
replaceable harness assembly that plugs into the board.
Through the sensors, the board detects outdoor ambient,
coil, and discharge temperature fault conditions. As the
detected temperature changes, the resistance across the
sensorchanges. Sensorresistancevaluescanbechecked
by ohming across pins .
NOTE - When checking the ohms across a sensor, be
aware that a sensor showing a resistance value that is
not within the range shown, may be performing as
designed. However, if a shorted or open circuit is
detected, then the sensor may be faulty and the sensor
harness will needs to be replaced.
Coil Sensor—The coil temperature sensor considers
outdoor temperatures below -35°F (-37°C) or above 120°F
(48°C) as a fault. If the coil temperature sensor is detected
as being open, shorted or out of the temperature range of
the sensor, the board will not perform demand or time/
temperature defrost operation and will display the
appropriate fault code. Heating and cooling operation will
be allowed in this fault condition.
Sensor Temperature
Range °F (°C) Red Led (DS1)
Outdoor
(Ambient)
Coil
Discharge (If
applicable)
Note: Sensor resistance decreases as sensed temperature increases.
Pins/Wire
Color
-35 (-37 to 120
(48) 280,000 to 3750 3 & 4 (Black)
-35 (-37) to 120
(48) 280,000 to 3750
24 (-4) to 350
(176) 41,000 to 103
5 & 6
(Brown)
1 & 2
(Yellow)
Sensor Temp. / Resistance Range

506318-01Page 10 of 17 Issue 0946
Ambient Sensor—The ambient sensor considers outdoor
temperatures below -35°F (-37°C) or above 120°F (48°C)
as a fault. If the ambient sensor is detected as being open,
shorted or out of the temperature range of the sensor, the
boardwill not perform demanddefrostoperation. The board
will revert to time/temperature defrost operation and will
display the appropriate fault code. Heating and cooling
operation will be allowed in this fault condition.
NOTE - Within a single room thermostat demand, if 5-
strikes occur, the board will lockout the unit. Defrost
board 24 volt power “R” must be cycled “OFF” or the
“TEST” pins on board must be shorted between 1 to 2
seconds to reset the board.
Defrost Temperature Termination Shunt (Jumper)
Pins—The defrost board selections are: 50, 70, 90, and
100°F (10, 21, 32 and 38°C). The shunt termination pin is
factory set at 50°F (10°C). If the temperature shunt is not
installed,thedefaulttermination temperatureis90°F (32°C).
DELAY MODE
Thedefrostboard has a field-selectablefunction to reduce
occasional sounds that may occur while the unit is cycling
in and out of the defrost mode. When a jumper is installed
on the DELAY pins, the compressor will be cycled off for 30
seconds going in and out of the defrost mode. Units are
shipped with jumper installed on DELAY pins.
NOTE - The 30 second off cycle is NOT functional when
jumpering the TEST pins.

Page 11 of 17506318-01 Issue 0946
OPERATIONAL DESCRIPTION
The defrost control board has three basic operational
modes: normal, calibration, and defrost.
Normal Mode—The demand defrost board monitors the O
line, to determine the system operating mode (heat/cool),
outdoorambienttemperature, coiltemperature(outdoorcoil)
andcompressorruntimetodeterminewhenadefrostcycle
is required.
Calibration Mode—The board is considered uncalibrated
when power is applied to the board, after cool mode
operation,orif the coil temperature exceeds thetermination
temperature when it is in heat mode.
Calibration of the board occurs after a defrost cycle to
ensure that there is no ice on the coil. During calibration,
thetemperatureofboth the coil and the ambient sensor are
measured to establish the temperature differential which is
required to allow a defrost cycle.
DefrostMode—The followingparagraphsprovideadetailed
description of the defrost system operation.
DETAILED DEFROST SYSTEM OPERATION
DefrostCycles—The demanddefrost controlboardinitiates
a defrost cycle based on either frost detection or time.
!Frost Detection—If the compressor runs longer than
30 minutes and the actual difference between the clear
coil and frosted coil temperatures exceeds the
maximum difference allowed by the control, a defrost
cycle will be initiated.
IMPORTANT - The demand defrost control board
will allow a greater accumulation of frost and will
initiate fewer defrost cycles than a time/temperature
defrost system.
!Time—If6 hours of heating mode compressor runtime
has elapsed since the last defrost cycle while the coil
temperature remains below 35°F (2°C), the demand
defrost control will initiate a defrost cycle.
Actuation—Whenthereversingvalve is de-energized, the
Y1 circuit is energized, and the coil temperature is below
35°F (2°C), the board logs the compressor run time. If the
board is not calibrated, a defrost cycle will be initiated after
30 minutes of heating mode compressor run time. The
control will attempt to self-calibrate after this (and all other)
defrost cycle(s).
Calibrationsuccess dependson stablesystem temperatures
during the 20-minute calibration period. If the board fails to
calibrate, another defrost cycle will be initiated after 45
minutes of heating mode compressor run time. Once the
defrost board is calibrated, it initiates a demand def rost
cyclewhenthe differencebetween the clear coil and frosted
coiltemperaturesexceeds the maximum differenceallowed
bythecontrol OR after6hours of heating mode compressor
run time has been logged since the last defrost cycle.
NOTE - If ambient or coil fault is detected, the board
will not execute the “TEST” mode.
Termination—The defrost cycle ends when the coil
temperature exceeds the termination temperature or after
14 minutes of defrost operation. If the defrost is terminated
bythe14-minute timer,another defrost cycle will beinitiated
after 30 minutes of run time.
Test Mode—WhenY1is energized and 24V power is being
applied to the board, a test cycle can be initiated by placing
the termination temperature jumper across the “Test” pins
for 2 to 5 seconds. If the jumper remains across the “Test”
pins longer than 5 seconds, the control will ignore the test
pinsand revert to normal operation. The jumper will initiate
one cycle per test.
Enter the “TEST” mode by placing a shunt (jumper)
across the “TEST” pins on the board after power-up. (The
“TEST” pins are ignored and the test function is locked out
ifthe shunt is applied on the “TEST” pins before power-up).
Board timings are reduced, the low-pressure switch is
ignoredand the board willclearany active lockoutcondition.
Each test pin shorting will result in one test event.
For each “TEST” the shunt (jumper) must be removed for
at least 1 second and reapplied. Refer to flow chart for
“TEST” operation.
Note: The Y1 input must be active (ON) and the “O”
room thermostat terminal into board must be inactive.
DEFROST BOARD DIAGNOSTICS
See defrost control board diagnostic LED table on next
pageto determine defrost board operational conditions and
to diagnose cause and solution to problems.

506318-01Page 12 of 17 Issue 0946

Page 13 of 17506318-01 Issue 0946
Defrost Control Board Diagnostic LEDs

506318-01Page 14 of 17 Issue 0946
H/P 13 SINGLE PHASE WIRING DIAGRAM

Page 15 of 17506318-01 Issue 0946
H/P 14 SEER WIRING DIAGRAM

506318-01Page 16 of 17 Issue 0946
Homeowner’s Information
ELECTRICAL SHOCK HAZARD!
Turn OFF electric power to unit before performing any
maintenance or removing panels or doors.
FAILURE TO DO SO COULD RESULT IN BODILY
INJURY OR DEATH.
WARNING
Heat Pump Operation
Your new heatpumphasseveral characteristics that you
should be aware of:
!Heat pumps satisfy heating demand by delivering
large amounts of warm air into the living space. This is
quite different from gas-or oil-fired furnaces or an electric
furnace which deliver lower volumes of considerably hotter
air to heat the space.
!Do Not be alarmed if you notice frost on the outdoor
coil in the winter months. Frost develops on the outdoor
coil during the heating cycle when temperatures are below
45F. An electronic control activates a defrost cycle lasting
5 to 15 minutes at preset intervals to clear the outdoor coil
of the frost.
!Duringthedefrost cycle, you may notice steam rising
from the outdoor unit. This is a normal occurrence. The
thermostat may engage auxiliary heat during the defrost
cycle to satisfy a heating demand; however., the unit will
runto normaloperation attheconclusion ofthe defrostcycle.
In case of extended power outage...
If the outdoor temperature is below 50F and power to
youroutdoorunit has been interrupted for 6hoursorlonger,
observe the following when restoring power to your heat
pump system.
!Set the room thermostat selector to the “Emergency
Heat” setting to obtain temporary heat for a minimum of 6
hours. This will allow system refrigerant pressures and
temperaturesenough time to returntoa stabilizedcondition.
!In Emergency Heat mode, all heating demand is
satisfied by auxiliary heat; heat pump operation is locked
out. After a 6 hour “warm-up” period, the thermostat can
thenbe switched tothe “Heat” settingandnormal heat pump
operation my resume.
!Heat pumps (in the cooling mode) remove humidity
from your home. Depending on the amount of moisture in
the air inside your home, water will trickle from the
condensate drain of the cooling coil.
Thermostat Operation
The wall-mounted thermostat controls your air condi-
tioner. The thermostatisavailable in various configurations
from different manufacturers. The
information below is typical for most thermostats. Ask your
dealer for specific information regarding the model of
thermostat installed.
Temperature Setting Levers
Mostheat pumpthermostatshave2temperature selector
levers: one for heating and one for cooling. Set the levers
ordials tothedesired temperaturesetpointsfor bothheating
andcooling. Avoidfrequenttemperature adjustment;turning
the unit off and back on before pressures equalize puts
stress on the unit compressor.
On heat pump systems, increasing your thermostat
setting by more than 2 degrees may cause supplemental
heaters to turn on, reducing potential energy savings.
Fan Switch
InAUTOorINT(intermittent)mode, the blower operates
only when the thermostat calls for heating or cooling. This
mode is generally preferred when humidity control is a
priority. The ON or CONTmode provides continuous indoor
blower operation, regardless of whether the compressor or
auxiliary heat are operating. This mode is required when
constant air circulation or filtering is desired.
System Switch
Set the system switch for heating, cooling or auto
operation. The auto mode allows the heat pump to
automatically switch from heating mode to cooling mode to
maintain predetermined comfort settings. Many heat pump
thermostats are also equipped with an emergency heat
mode which locks out heat pump operation and provides
temporary heat supplied by the auxiliary heat.
Indicating Light
Most heat pump thermostats have an amber light which
indicateswhen the heatpumpis operating intheemergency
heat mode.
Temperature Indicator
The temperature indicator displays the actual room
temperature.
Fan Control
Forfan controlyourthermostatmay haveaFan Selection
Switchthatallows you to run the fan continuously or cycle it
automatically with the heating or cooling system. Switch
the lever to ON for continuous operation and to AUTO for
automatic cycling.
For maximum comfort satisfaction and continual air
cleaning/filtering, constant fan operation is recommended.

Page 17 of 17506318-01 Issue 0946
Onmodels without a fan Selection Switch, the fan will cycle
with the outdoor unit.
Important System Information
!Yoursystem should neverbe operated withouta clean
air filter properly installed.
!Returnair and supply airregistersshould be free from
restrictions or obstructions to allow full flow of air.
Regular Maintenance Requirements
Your system should be regularlyinspectedbyaqualified
servicetechnician. These regular visitsmayinclude(among
other things) checks for:
!Motor operation
!Ductwork air leaks
!Coil & drainpan cleanliness (indoor & outdoor)
!Electrical component operation & wiring check
!Proper refrigerant level & refrigerant leaks
!Proper airflow
!Drainage of condensate
!Air filter(s) performance
!Blower wheel alignment, balance & cleaning
!Primary & secondary drain line cleanliness
!Proper defrost operation (heat pumps)
Thereissome routine maintenance procedures you can
dotohelpkeep your system operating at peak performance
between visits.
Air Filter
Inspect air filters at least monthly and replace or clean
as required. Disposable filters should be replaced.
Washable filters may be cleaned by soaking in mild
detergent and rinsing with cold water. Replace filters with
the arrows pointing in the direction of airflow. Dirty filters
are the most common cause of poor heating / cooling
performance and compressor failures.
Indoor Coil
If the system has been operated with a clean filter in
place, it should require minimal cleaning. Use a vacuum
cleaner and soft brush attachment to remove any
accumulation of dust from the top and underside of the
finned coil surface. However, perform this maintenance
only when the coil is completely dry.
If the coil cannot be cleaned by this method, call your
dealer for service. It may need a detergent solution and
rinsing with water for cleaning, which may require coil
removal. You should not attempt this yourself.
Condensate Drain
During cooling season check at least monthly for free
flow of drainage and clean if necessary.
Condenser Coils
Grasscuttings,leaves, dirt, dust, lintfromclothesdryers,
and fall off from trees can be drawn into coils by movement
of the air. Clogged condenser coils will lower the efficiency
of your unit and could cause damage to the condenser.
Periodically, debris should be brushed from the
condenser coils.
SHARP OBJECT HAZARD!
Condenser coils have sharp edges. Wear adequate
body protection on body extremities (e.g. gloves).
FAILURE TO FOLLOW THIS WARNING COULD
RESULT IN BODILY INJURY.
WARNING
Use a soft bristle brush with light pressure only. DO NOT
damageor bend condenser coil fins. Damaged or bent fins
may affect unit operation.
Painted Surfaces
Formaximum protection of the unit’sfinish, a good grade
of automobile wax should be applied every year. In
geographical areas where water has a high concentration
of minerals (calcium, iron, sulfur, etc.). It is recommended
that lawn sprinklers not be allowed to spray the unit. In
such applications, the sprinklers should be directed away
from the unit. Failure to follow this precaution may result in
premature deterioration of the unit finish and metal
components.
Insea coast areas, special maintenance is required due
to the corrosive atmosphere provided by the high salt
concentration in ocean mists and the air. Periodic washing
of all exposed surfaces and coil will add additional life to
your unit. Please consult your installing dealer for proper
procedures in your geographic area.
IF YOUR SYSTEM DOES NOT WORK, BEFORE
REQUESTING A SERVICE CALL:
1. Ensure thermostat is set below (cooling) or above
(heating) room temperature and that the system lever is in
the “COOL”, “HEAT” or “AUTO” position.
2. Inspectyourreturnairfilter: Ifit isdirty yourair conditioner
may not function properly.
3. Check indoor and outdoordisconnectswitches. Confirm
circuitbreakersareON or that fuses have not blown. Reset
breakers/replace fuses as necessary.
4. Inspect the outdoor unit for clogged condenser coils,
(grass cuttings, leaves, dirt, dust or lint). Ensure that
branches, twigs or other debris are not obstructing the
condenser fan.
IF YOUR SYSTEM STILL DOES NOT OPERATE,
CONTACT YOU SERVICING DEALER.
Be sure to describe the problem, and have the model
and serial numbers of the equipment available.
If warranted replacements parts are required, the
warrantymustbeprocessedthroughaqualified distribution
location.