Nordyne iq Drive FT4BG Series User manual

Split System Heat Pump
FT4BG & PSH4BG Series
INSTALLATION INSTRUCTIONS
18 SEER
The 18 SEER, iQ Drive®split heat pump operates as part of a larger system which can provide temperature, air flow, and
humidity control for a residence or other similarly sized building. This system includes this outdoor unit and a compatible
indoor unit, typically an air handler with electric strip heat or a gas furnace. The electric or gas heat may serve as backup
or auxiliary heat to supplement the heat pump, which is expected to serve as the primary heating means. However, electric
or gas heat is not required for this system to operate. Accessory equipment which may be used with the system includes
humidifiers, electric or electronic air cleaners, and U/V (ultraviolet) sterilizing lamps.
Refer to the System Operation section within this document for a description of how the heat pump operates. In addition,
information for troubleshooting and diagnosing problems is included.
OTHER REFERENCE DOCUMENTS
• Installation instruction documents for indoor equipment
(furnace or air handler, optional humidifier, etc.)
• localwiringandbuildingcodes
• NordyneApplicationGuidelineforRefrigerantLinesOver
75 Feet, document 044B-0600
• Operation/congurationmanualfortwo-stagethermostat
(existing or newly installed)
DO NOT DESTROY. PLEASE READ CAREFULLY AND
KEEP IN A SAFE PLACE FOR FUTURE REFERENCE.
IMPORTANT
ATTENTION INSTALLERS:
It is your responsibility to know this product
better than your customer.This includes being
able to install the product according to strict
safety guidelines and instructing the customer
onhowtooperateandmaintaintheequipmentfor
the life of the product. Safety should always be
the deciding factor when installing this product
and using common sense plays an important
role as well.Pay attention to all safety warnings
and any other special notes highlighted in the
manual. Improper installation of the furnace or
failure to follow safety warnings could result in
serious injury, death, or property damage.
These instructions are primarily intended to
assist qualified individuals experienced in the
proper installation of this appliance. Some
localcodesrequirelicensedinstallation/service
personnel for this type of equipment. Please
read all instructions carefully before starting
the installation.Return these instructions to the
customer’s package for future reference.
IMPORTANT SAFETY INFORMATION ........................2
PREPARATION.............................................................3
Slab Mounting..............................................................3
Roof Mounting..............................................................3
ELECTRICAL CONNECTIONS....................................4
Electrical Power Wiring ................................................4
Control Circuit Wiring...................................................4
REFRIGERANT LINE CONNECTIONS........................4
LineDesignandRouting..............................................4
Brazing.........................................................................5
System Evacuation ......................................................5
Refrigerant Charging....................................................5
Charging Operation......................................................5
Alternate Procedure for Charging a Heat Pump
in Cooling Mode...........................................................6
Alternate Procedure for Charging a Heat Pump
in Heating Mode...........................................................6
SYSTEM OPERATION..................................................6
Thermostat...................................................................6
Run Sequence .............................................................6
Blower Flow Rates .......................................................7
Delay Override.............................................................7
Defrost Cycle................................................................7
Auxiliary Heat...............................................................7
Diagnostic Display........................................................7
Instrumentation ............................................................7
MAINTENANCE............................................................8
FIGURES & CHARTS...................................................9
Figure 2. Heat Pump Control Panel ...........................9
Figure 3. Power Wiring Terminals.............................10
Figure4.LowVoltageCompartment........................10
Figure 5. Service Valves...........................................10
Figure 6. Charging Charts........................................11
Figure 7. Interface Board in Control Panel...............12
Figure 8.Wiring Diagram (2-4 Ton Models)..............13
Figure 9.Wiring Diagram (5 Ton Models).................14
Figure 10.Temperature Sensor Resistance Carts...15
INSTALLATION / PERFORMANCE CHECK LIST.....16

2
IMPORTANT SAFETY INFORMATION
INSTALLER:Pleasereadallinstructionsbeforeservicingthis
equipment.Pay attention to all safety warnings and any other
special notes highlighted in the manual.Safety markings are
usedfrequentlythroughoutthismanualtodesignateadegree
orlevel of seriousness andshould notbe ignored.WARNING
indicates a potentially hazardous situation that if not avoided,
could result in personal injury or death.CAUTION indicates a
potentially hazardous situation that if not avoided, may result
in minor or moderate injury or property damage.
WARNING:
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failuretofollowsafetywarningsexactlycouldresult
in serious injury or property damage.
Improper servicing could result in dangerous
operation,seriousinjury,deathorpropertydamage.
• Beforeservicing,disconnectallelectricalpower
to the equipment.
• Whenservicingcontrols,labelallwirespriorto
disconnecting. Reconnect wires correctly.
• Verifyproperoperationafterservicing.
WARNING:
iQ Drive Split System Heat Pumps are shipped
charged with R410A refrigerant and ready for
installation.When systemisinstalled accordingto
these instructions,additional refrigerant charging
may or may not be required. If repairs make it
necessary for evacuation and charging, it should
only be attempted by qualified trained personnel
thoroughly familiar with this equipment. Under no
circumstances should the owner attempt to install
and/or service this equipment. Failure to comply
withthiswarningcouldresultin property damage,
personal injury, or death.
CAUTION:
ThisunitusesrefrigerantR-410A.DONOTuseanyother
refrigerant in this unit. Use of another refrigerant will
damage the unit.
WARNING:
Unless noted otherwise in these instructions, only
factory authorized parts or accessory kits may be
used with this product. Improper installation, service,
adjustment, or maintenance may cause explosion,fire,
electrical shock or other hazardous conditions which
may result in personal injury or property damage.
WARNING:
The information listed below and the next page
must be followed during the installation, service,
and operation of this equipment. Failure to follow
safety recommendations could result in possible
damage to the equipment,serious personal injury
or death.
• Theinstallermustcomplywithalllocalcodesandregulations
which govern the installation of this type of equipment.
Local codes and regulations take precedence over any
recommendationscontainedintheseinstructions.Consult
localbuildingcodesandtheNationalElectricalCode(ANSI
CI) for special installation requirements.
• Allelectricalwiringmustbecompletedinaccordancewith
local, state and national codes and regulations and with
theNationalElectricCode(ANSI/NFPA70)orinCanada
the Canadian Electric Code Part 1 CSA C.22.1.
• This equipment contains liquid and gaseous refrigerant
underhighpressure.DONOTUSEANYPORTIONOFTHE
CHARGEFORPURGINGORLEAKTESTING.Installation
or servicing should only be performed by qualified trained
personnel thoroughly familiar with this type equipment.
• Installationofequipmentmayrequirebrazingoperations.
Installer must comply with safety codes and wear
appropriatesafetyequipment(safetyglasses,workgloves,
fireextinguisher,etc.)whenperformingbrazingoperations.
• Follow all precautions in the literature, on tags, and on
labels provided with the equipment.Read and thoroughly
understand the instructions provided with the equipment
priortoperformingtheinstallationandoperationalcheckout
of the equipment.
• Use caution when handling this appliance or removing
components. Personal injury can occur from sharp metal
edges present in all sheet metal constructed equipment.
• Fullyannealed,refrigerantgradecoppertubingshouldbe
used when installing the system. Refrigerant suction line
tubing should be fully insulated.
• This unit is designed for outdoor installations only and
should be positioned as described on page 3.

3
PREPARATION
BeforeproceedingwithinstallationofiQheatpumpequipment,
consultwiththedistributorandhomeownertoconfirmthatthe
equipment listed on the order is what was ordered, and that
it matches labeling on the equipment packaging.
Determine (including consultation with the homeowner) the
intended/preferred location for placement of the compressor/
outdoor coil unit. Unit envelope dimensions are shown in
Figure 1.
This heat pump is designed for outdoor installation only.
Unit placement must take into consideration the following
clearances:
• A minimum of 12 inches must be provided between each
of the four sides and any solid barrier or wall which might
block free inlet air flow into the coil.A minimum clearance
of 18 inches is required between multiple units.
• The corner of the unit covered by the control access cover
must be clear enough to allow comfortable access by a
serviceperson.
• Thetopoftheunitmustbeopenandunobstructedtoprevent
recirculationofoutdoorfandischargeair,particularlyforair
conditioningusage.Aminimumdistanceof4feetoverhead
clearance is recommended.Do not locate the unit in a pit
with high walls on all sides.
Locate the unit away from overhangs which would allow
water runoff or ice to fall directly onto the heat pump. In low
temperature climates, place the unit where it is not directly in
prevailing winds. Avoid placing the heat pump near sleeping
quarters or windows.As the unit goes through defrost cycles,
a change in sound will occur.
Slab Mounting
• Thepreferredunitmountingisonanoutdoorslab(concrete
or plastic), on the ground, in an area with good drainage
unlikely to be affected by heavy runoff, ground settling, or
deep snowdrift accumulation.
• The support slab should be level. If the area is subject to
heavy snowfall or drift accumulation, the use of a snow
stand is recommended as well. Make sure that the drain
holes in the bottom of the unit are not obstructed.
Roof Mounting
The method used for roof mounting should be designed so
as not to overload roof structures nor transmit noise to the
interiorofthestructure.Refrigerantandelectricallinesshould
be routed through suitably waterproofed openings to prevent
leaking into the structure. Make sure that the roof structure
can adequately support the weight of the equipment.Consult
local building codes for rooftop installations.
After a location has tentatively been selected, trace routing
of new (or pre-existing) refrigerant lines (two), and power and
control wiring. See further discussion below.
• Maximumrecommendedlengthforrefrigerantlines:100
ft.
• Maximumelevationdifference,compressorbasetoindoor
coilbase(compressorhigherorlower):50feet.NOTE: An
oil trap is required for elevations exceeding 50 feet.
• Refrigerantlines should NOTbeburied. (in concreteor
otherwise).
• RefertoNordyneApplicationGuidelineforRefrigerantLines
Over 75 Feet document 044B-0600, for piping details.
Oncetheaboveinformationhasbeenconfirmedandpotential
questions regarding location, refrigerant line routing, and
wire routing have been resolved, proceed with unpacking the
equipment.It is strongly recommended that inspection of the
hardware be performed prior to bringing it to the installation
site.Inspect for cosmetic as well as functional damage (such
as obvious holes or gaps in tubes and joints, cut or pinched
wires or wire insulation).
Verify that the iQ Drive®heat pump unit package includes the
following:
• Coil/compressor/controlunit.
• Packetcontaininginstallationinstructionsandonelter-
drier.
Figure 1. Unit Envelope Dimensions
EXTERIOR WALL
CONTROL
PANEL
24”
For Service
Access
12”
12”
12”

4
ELECTRICAL CONNECTIONS
WARNING:
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failuretofollowsafetywarningsexactlycouldresult
in serious injury or property damage.
Improper servicing could result in dangerous
operation,seriousinjury,deathorpropertydamage.
• Beforeservicing,disconnectallelectricalpower
to the equipment.
• Whenservicingcontrols,labelallwirespriorto
disconnecting. Reconnect wires correctly.
• Verifyproperoperationafterservicing.
Electrical Power Wiring
Electrical power wiring shall comply with the current
provisionsoftheNationalElectricalCode(ANSI/NFPA70)as
supplementedbyapplicablelocalbuildingcodes.Theinstaller
shouldbecomefamiliarwiththewiringdiagrambeforemaking
electricalconnectionstotheoutdoorunit.Anequipmentwiring
diagramisincludedinthisinstruction(Figures8&9,pages13
& 14) and inside the unit control panel cover.Refer to the unit
rating label located on the exterior of the control box cover for
operating voltage, minimum circuit ampacity, and maximum
fuse size. See Table 1 for wire sizing.
COPPERWIRESIZE-AWG(1%VoltageDrop)
Supply Circuit
Ampacity SupplyWire Length - Ft
up to 50 51 - 100 101 - 150 151 - 200
15 14 10 8 6
20 12 8 6 4
25 10 8 6 4
30 10 6 4 4
35 8 6 4 3
40 8 6 4 3
45 6 4 3 2
50 6 4 3 2
Wire Sized based on N.E.C. for 60°C type copper conductors
Table 1. Copper Wire AmpacityTables
• Electrical connections to the heat pump are made at the
bottom of the control panel compartment. Remove the
control panel cover to gain access to this compartment.
Figure2(page9)showsatypicalcontrolpanelcompartment.
• Aproperlysizedbranchcircuitanddisconnectswitchmust
be installed where it is easily accessible and within line of
sight of the outdoor unit.
• Remove the control panel cover. Route the power and
ground wires (3 wires, including earth ground) from the
disconnectboxtotheunit.Useofoutdoor shieldedconduit
(metal lined Sealtite®) is required. The electrical conduit
opening is located on the right side of the panel forming
the bottom of the control compartment. See Figure 2.
• Connect the power wires to L1 and L2 box lugs of the
contactor,andthegroundwiretothegroundingluglocated
tothe rightof the contactor.Referto Figures 2and 3 (page
10). Only copper wires should be used.
• Replacethecontrolpanelcoverbeforeapplyingpower.
Control Circuit Wiring
The heat pump is designed to operate with a 24 vac Class
II control circuit. Control circuit wiring must comply with the
latestversionoftheNationalElectricalCode(ANSI/NFPA70)
as supplemented by local building codes.
In general, 24 vac control power wiring must be run to
interconnect the two-stage thermostat, the indoor unit, and
theoutdoorunit.Thesourceofthe 24vacislocatedwithinthe
indoor unit (air handler or furnace).The Cside of this power
sourcemaybegroundedorungrounded,typicallydetermined
by the indoor equipment electrical design.
In general, 6 wires must be run to the heat pump’s control
panel. R, C, and W2 will connect to the indoor unit. Y1, Y2,
O, and L(if used) originate at the thermostat.W2 provides a
signal to turn on auxiliary (indoor) heat during a defrost cycle.
The optional seventh Lprovides a fault indication for some
White-Rodgers thermostats.
Pass each field-run control wire into the hole in the lower left
sideofthebaseoftheheatpump’scontrolpanelcompartment.
Refer to Figures 2 and 4.Connect each of the field-run wires
to its corresponding factory wired lead (with stripped ends)
using a wire nut or other solderless connector within the low
voltage compartment. See Table 2 below.
Wire Color
(OutdoorUnit) ID Function Indoor Connection
RED R24VAC Air Handler
or Furnace
BLK C24 VAC common
or ground
WHT W2 Heat during defrost
YEL Y1 1st Stage call
Thermostat
BLU Y2 2nd Stage call
ORN OHeat (RV)
BRN *L *Fault indication
* Usage optional
Table2.24VoltControlWiring
REFRIGERANT LINE CONNECTIONS
Line Design and Routing
Refrigerant lines must be connected by a licensed EPA
certified technician following sound established installation
practice.Once the heat pump location has been determined
and the unit set in place the refrigerant lines should be routed
and connected.
• Refrigerantlinesshouldfollowadirectpathfromtheindoor
coil to the outdoor unit avoiding sharp bends.When lines
passthroughwalls,makesuretoproperlysealandsupport
them so that vibration is not transmitted to the structure.
• Refrigeranttubingshouldbesupportedinamannerwhich
assures that the tubing will not vibrate or wear as a result
of contact with sharp materials or edges during system
operation.

5
• Linesmustbecleanrefrigeration-gradecopper.
• Avoidremovingcapsandplugsfromtheheatpumporlines
until they are ready to be connected.
• Insulatethevaporlinewithrefrigerantlineinsulation¼”
wall thickness or greater.
Proper system performance and oil management depend
on properly selecting the liquid and vapor line sizes.Refer to
Table 3 below for the proper size of field supplied lines.The
maximum allowable refrigerant line length is 100 ft.
Model
Line Set Lengths
VaporLine Liquid
Line
up to
24 ft. 25 to 39 ft. 40 to 75 ft. 75 to 100 ft. up to 100 ft.
-024K Units 3/4 in.
(19 mm) 7/8 in. (22 mm) 1 1/8 in. (29 mm) 3/8 in. (10 mm)
-036K Units 7/8 in.
(22 mm) 1 1/8 in. (29 mm) 3/8 in. (10 mm)
-048K Units 7/8 in.
(22 mm) 1 1/8 in. (29 mm) 3/8 in. (10 mm)
-060K Units 7/8 in.
(22 mm) 1 1/8 in. (29 mm) 3/8 in. (10 mm)
Table 3. Permissible Refrigerant Line Sizes
The maximum vertical elevation between the heat pump and
indoor coil is 50 ft. Systems that require more elevation will
need to have an oil trap installed in the vapor line. Refer to
NordyneApplicationGuidelineforRefrigerantLinesOver75
Feet (document 044B-0600) for piping details.
A filter drier is supplied with the heat pump.It is required and
recommended that it be installed near the indoor coil.
It is recommended to replace existing refrigerant lines that
were previously used for an R-22 system.If the lines are not
replaced, they must be properly flushed by a licensed EPA
certified technician in accordance with the manufacturer’s
instructions and established procedures.
Brazing
Use the appropriate safety equipment while brazing. Items
such as gloves, safety glasses, proper ventilation, and a fire
extinguisher should be used.
1.Routetherefrigerantlinesfromtheindoorcoiltotheservice
valves on the heat pump. Avoid sharp radius bends and
turns. See Figure 5 (page 10)
2.Make sure that the vapor line is properly insulated for the
entire length of the run for maximum system efficiency.
Improperinsulationmayalsocreatecondensationandresult
in water damage to the equipment and building structure.
3.Removethevalvecoresfromtheheatpumpservicevalves.
Wrap the valves completely with wet rags to protect them
from overheating during the brazing operation.
4.Connect both the vapor and liquid lines. Tubes should be
round, de-burred and free of debris. Use a phosphorous
and copper or silver brazing alloy for the joints.Do not use
soft solder with a low melting point.
5.Connect the indoor lines according to the indoor unit
instructions.Theindoorcoilwillrequirethesamealloysand
wet rags to protect the sensors from excessive heat on the
refrigerant lines.
6.Allowtheservicevalvestocoolandreplacethevalvecores.
7.Leaktesttheconnectionsusinglowpressuredrynitrogen.
System Evacuation
1.Connect the refrigerant gauge manifold to both the vapor
and liquid service valves.See Figure 5.Connect the center
port to the vacuum pump.
2.Open both manifold valves and start the vacuum pump.
After a short time, it is recommended to close the manifold
valves and stop the vacuum pump to look for a rapid loss
ofvacuum.Lossofvacuumindicatesthatthereisaleakin
the system. Repeat the leak test if required.
3.Evacuate the system to at least 500 microns to remove
non-condensables and water vapor. Close the manifold
valves and remove the vacuum pump.
4.Connect the refrigerant tank to the center manifold port of
the gauge set.Pressurize the system enough to break the
vacuum.
5.Openbothservicevalvesbyturningthevalvestems¼turn
counterclockwise. The stem will be in line with the tubes.
Replacethestemcapsandtighten.ProceedwithRefrigerant
Charging section.
WARNING:
The heat pump system contains liquid and
gaseous refrigerant under pressure. Adjustment
of refrigerant charge should only be done by a
qualified, EPA certified technician thoroughly
familiar with this type of equipment. Under no
circumstances should the homeowner attempt to
install and/or service this equipment. Failure to
complywiththiswarningcouldresultinequipment
damage, personal injury, or death.
Refrigerant Charging
NOTES:
• Theunit must be charged at a fixed speed setting.For this
purpose the thermostat needs to be wired and powered
prior to charging.
• Theheatpumpisfactorychargedforeldinstalledlines15
ft.inlengthwiththematchingindoorequipment.Adjustments
to the refrigerant charge will be required for other length
andtubesizes.Forlineslongerthan15ftwitha3/8”OD
liquid line, add 0.52 oz.per ft. See Table 4 (page 6).
• Smallvariationsin the temperatures and pressures are
normal due to differences in the installation.
• Large variations in the temperatures and pressures
could indicate incorrect charge or another problem with a
component in the system.
The preferred method of charging is by weighing in the
additional refrigerant required. If a charging scale is not
available, the next preferred charging method would be to
use the sub-cooling method in cooling mode.
Charging Operation
For charging in the field, the unit should be run with a
call for second stage cooling (or heating, if the outdoor
ambient temperature is below 60° F), with both Y1 and Y2

6
outputs energized.This may be accomplished by setting the
thermostat to cool with a setpoint substantially lower than
room temperature.This will provide 60 minutes of operation
at the nominal rating speed (interface board display “C4”or
“H4”)before thereisaspeedchange(toa higherspeed).
If this speed change occurs before the charging process is
complete, turn the system off, then restart the process.
MODEL 2TON
(-024K)
3TON
(-036K)
4TON
(-048K)
5TON
(-060K)
Factory Charge
for 15 ft.line set 188 oz 184 oz 282 oz 282 oz
Additional Charge
for 40 ft.line set 16 oz 16 oz 18 oz 18 oz
Additional Charge
for 75 ft.line set 39 oz 43 oz 44 oz 44 oz
Additional Charge
for 100 ft.line set 57 oz 62 oz 63 oz 63 oz
Table 4. Refrigerant Charge Quantities
Alternate Procedure for Charging Heat Pump in Cooling
Mode(withoutdoortemperaturesabove60°F)Basedon
Subcooling:
While charging based on weight is preferred, this method is
acceptable. Use this method when the outdoor temperature
is 60 ° F or higher to verify the correct charge in cooling
mode. The indoor temperature should be between 70 ° F
and 80° F.
1.Connectthe gauge manifoldtothe liquid and vaporservice
valves. See Figure 5 (page 10).
2.Start the system in cooling mode. Allow the system to run
15 minutes to stabilize.
3.Record the liquid refrigerant pressure in psig at the service
valve.
4.Record the liquid refrigerant line temperature in °F at the
service valve.
5.Using the temperature value recorded, determine the
corresponding liquid refrigerant pressure from the upper
curve(forcooling)inthechargingchart.SeeFigure6(page
11).
6.If the pressure measured in step 3 is less than the required
liquid refrigerant pressure determined in step 5, then
refrigerant needs to be added.
7.If the pressure measured in step 3 is greater than the
required liquid refrigerant pressure determined in step 5,
then the system is over-charged.
8.Add or remove charge from the system depending on the
measurements recorded. Allow the system to stabilize for
15 minutes before taking the next readings.
Alternate Procedure for Charging Heat Pump in Heating
Mode(withoutdoortemperaturesbelow60°F)Basedon
Subcooling:
Use this method when the outdoor temperature is 60° F or
lower to estimate the correct charge in heating mode. The
indoor temperature should be between 65° F and 75° F.
The preferred method of charging is by weighing in the
additional refrigerant required. If a charging scale is not
available,thecorrectchargecanbeestimatedbythismethod.
Refrigerant can be stored in the receiver and accumulators
and result in an over-charged system.If it is necessary to use
this method, follow up service should be scheduled when
the temperature is above 60° F, and then charge should be
verified in cooling mode.
1.Connect the gauge manifold to the liquid service valve and
suction service port located at the left side of the access
panel above the liquid service valve. See Figure 5 (page
10).
2.Start the system in heating mode.Allow the system to run
15 minutes to stabilize.
3.Record the liquid refrigerant pressure in psig at the service
valve.
4.Record the liquid refrigerant line temperature in °F at the
service valve.
5.Using the temperature value recorded, determine the
corresponding liquid refrigerant pressure from the lower
curve(forheating)inthechargingchart.SeeFigure6(page
11).
6.If the pressure measured in step 3 is less than the required
liquid refrigerant pressure determined in step 5, then
refrigerant needs to be added.
7.If the pressure measured in step 3 is greater than the
required liquid refrigerant pressure determined in step 5,
then the system is over-charged.
8.Add or remove charge from the system depending on the
measurements recorded. Allow the system to stabilize for
15 minutes before taking the next readings.
NOTE: Small variations in charge will have a more significant
effect on liquid line pressure in heating mode compared to
cooling
SYSTEM OPERATION
Thermostat
Theprimarycontrolfortheoverallheatingandcoolingsystem
is provided by the indoor thermostat.Any standard two-stage
heat pump capable thermostat will be sufficient for operation.
Refer to the manual for the thermostat selected or installed
for configuration and usage details.
Run Sequence
Beforethe first start after power-upand betweencycles there
willalwaysbeafiveminute(re)startdelayimposed.Withacall
for heat pump heating or cooling and before the compressor
is turned on, the outdoor fan will run for one minute to assure
that the outdoor temperature measurement is close to that of
the ambient air.The compressor will then ramp up to a speed
selected by the capacity control scheme.
The18SEERheatpumpisatruevariablespeedunit.Normally
the heat pump compressor will operate at one of 5 speeds in
cooling and 5 in heating, each predetermined for a balance
ofoptimum efficiencyand capacity.The outdoor fanmotor will
also operate at multiple speeds, following the compressor.
For either heating or cooling mode, the speeds used will
dependonseveralfactors,including:
• Whetherfirst or second stage operationis called forbythe
thermostat (which must be two stage-capable),
• Outdoor ambient temperature.
• Thelengthoftimetheequipmenthasbeenoperatingduring
the current cycle
• The operating speed history, for both the current and the
previous operating cycles.

7
DISPLAY CAPACITY STAGE
C1 Cooling,StageOneCall,Low
C2 Cooling, Stage One Call, Intermediate
C3 Cooling,StageOneCall,LowHigh
C4 Cooling,StageTwoCall,NominalHigh
C5 Cooling, Stage Two Call, Boost
H1 Heating,StageOneCall,Low
H2 Heating, Stage One Call, Intermediate
H3 Heating,StageOneCall,LowHigh
H4 Heating,StageTwoCall,NominalHigh
H5 Heating, Stage Two Call, Boost
0L Startup Delay (5 minutes)
_System Powered but Idle
0F In Defrost
Table 5. Interface Board Operating Codes
For example, with a first stage call in cooling, if the setpoint
was satisfied quickly, the unit will restart the next time at a
lower speed.At a low or intermediate speed, if the setpoint is
not satisfied within 45 minutes, the speed will be increased.
If the unit cycles off after having a speed increase, the entire
next cycle will be at the higher speed. Also, the outdoor fan
will run for an extra minute after the compressor shuts off.
The actual current operating compressor speed can be
determinedbycheckingthe2-characterdisplayontheinterface
board. Refer to Figure 7 (page 12) and Table 5 (page 7).
Control operation is protected under U.S. patent number
US 8,011,199 B1
Blower Flow Rates
Depending on the indoor equipment installed, blower air flow
may be adjustable. When paired with a matching model air
handler or gas furnace, the airflow is set by DIP switches on
the blower control board, providing one flow for second stage
compressorspeedsandalowerflowforfirststagecompressor
speeds.Refertotheindoorequipmentmanualsforinstructions
onhowtoselectthedesiredairflows.Highstageairflowsused
forequipmentratingsareasfollows:
• 2ton-800cfm
• 3ton-1200cfm
• 4ton-1350cfm
• 5ton-1500cfm
Refertoindoorequipmentinstallationinstructionsforoptions,
operation, and field wiring relating to dehumidification and
humidification.
Delay Override
Whenperformingstartuptestsortroubleshooting,the5minute
startup delay can be skipped by shorting the two J4Test pins
indicatedinFigure7forabout1secondwhilethecompressor
is off and waiting to start.NOTE:This will also clear the faults
stored in memory.
Defrost Cycle
Thisequipmentfeaturesanadaptivedemanddefrostinheating
mode, which is enabled when the outdoor coil temperature
is below 35° F. After approximately 35 minutes of operating
in this condition for the first time, a defrost will be forced to
checkthedifferencebetweenthecoiltemperatureandoutdoor
air temperature, with the coil unfrosted.Subsequent defrosts
will be triggered when this temperature difference increases
(coil temperature drops) by an additional 6° F, referenced to
the outdoor ambient at that time.If this has not occurred by 6
hours of operation (with the coil below 35°), a defrost will be
runregardless.Followingeachdefrostsequence,theunfrosted
air-to-coiltemperaturedifferenceisrechecked,andthatvalue
is used to determine the next defrost trigger temperature. In
this way the effect of frosting up is always compared to the
unfrosted performance of the coil in its current condition.
During every defrost cycle the compressor first shuts off, the
reversingvalveshifts,thecyclereversestoheatuptheoutdoor
coil until the coil reaches the defrost termination temperature
setting(70°Fbydefault),thenthecompressorshutsoffagain
forthereversingvalvetoshiftbacktotheheatingmode.During
the following 8 minutes (approximately) the unit will heat at
nominal speed to perform the coil differential temperature
check described above, after which the system will return to
normal heating capacity control.
If a defrost termination temperature setting other than 70° is
desired,itcanbeadjustedbetween50°Fand80°Fbyplacing
ajumper betweenpairs ofpins on J1near the lowerright side
of the interface board inside the control panel (Figure 7). A
jumper is not required, however.
The defrost cycle may be artificially triggered for service and
troubleshooting purposes. With the unit running in heating
mode, simply short together the two J4 Test pins shown in
Figure 7 for about 1 second. NOTE: This will also clear the
faults stored in memory. The 2-character display will show
“0F”whenthedefrostcycleisunderway.
Auxiliary Heat
During the coil heating phase of each defrost cycle, the 18
SEER iQ heat pump will call for auxiliary heat (electric strip
heat or gas furnace). Depending upon the features and
functionality of the installed thermostat, auxiliary heat may
also be turned on in the case of a faulted heat pump, if the
heat pump cannot satisfy heating demand, or if outdoor air
temperatureisbelowa“balancepoint”setting.
Diagnostic Display
The interface board located inside the control panel has a
two character display which provides information regarding
operationalstatusandfaulthistory.When24vaccontrolpower
isprovidedtotheboard,thedisplaywillshowsomecombination
of characters.In order to diagnose a problem with the unit, or
to determine its operational status, remove the control panel
cover, then observe the 2-character lighted display on the
interface board. Refer toTables 5 (page 7) and 6 (page 8).

8
MAINTENANCE
WARNING:
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failuretofollowsafetywarningsexactlycouldresult
in serious injury or property damage.
Improper servicing could result in dangerous
operation,seriousinjury,deathorpropertydamage.
• Beforeservicing,disconnectallelectricalpower
to the equipment.
• Whenservicingcontrols,labelallwirespriorto
disconnecting. Reconnect wires correctly.
• Verifyproperoperationafterservicing.
• Inspecttheindoor airltermonthly.Cleanor replaceit
at the start of each heating and cooling season or when
an accumulation of dust or dirt is visible. If the indoor coil
needstobecleaned,contactaqualifiedservicetechnician.
• Inspectthecondensatedisposallinefromtheindoorcoil
at the beginning of the cooling season to make sure it is
not obstructed.
• Removeanyleaves,grassclippings,anddebrisfromthe
outdoorunitcoil,beingcarefulnottodamagethealuminum
fins. Dirt may be cleared from the coil by using a water
hose directed through the discharge fan grille toward the
outside of the unit.
• Haveayearlyinspectionbyaqualiedservicetechnician
toensurethatthesystemisperformingatitsoptimumlevel.
• Atleastonceaseasonopenthecontrolpanel(withpower
off) to inspect for and clear out insect structures and/or
cobwebs which might impede airflow through the control
panel compartment and the air inlet louvers at the bottom
of the control compartment.
DISPLAY CAPACITY STAGE
01 Inverter Power Module Overcurrent
02 GeneralInverterDriveFault
03 High Compressor Current
04 Current Sampling Error (Inverter)
05 High Inverter Heat Sink Temperature
06 High DC Bus Voltage (Inverter)
07 LowDCBusVoltage(Inverter)
08 LowLineVoltageatInverter
09 LineOvercurrentatInverter
10 LineVoltageSamplingError(Inverter)
11 LossofCommunication(InverterInternal)
12 Inverter Heat Sink Sensor Failure
13 LossofCommunication(InverterInternal)
14 LossofCommunication(IFBtoInverter)
15 Override, High Compressor Current
16 Override,HighLineCurrent
17 Override, High Inverter Heat Sink Temp
18 Outdoor Fan Motor Fault
19 LowPressureSwitchOpen
20 High Compressor Discharge Temperature
21 Interface Board Software Error
22 SensorFailure-SuctionLineTemp
23 Sensor Failure - Compressor Dischg Temp
24 Sensor Failure - Ambient Temperature
25 Sensor Failure - Coil Temp #1, Defrost
26 Sensor Failure - Suction Pressure Transdcr
27 Blower Motor Fault
28 Blower Communication Fault
29 CoolingLowTempLockout
Table 6. Interface Board Diagnostic Codes
The display will alternate between an operating code (Table
5) and a list of the codes for up to the last 20 different faults
or warnings. When this list is being displayed, each fault or
warning code in memory will be displayed for 5 seconds. If
one of the stored coded conditions occurs again, no repeat
entry will be made. Thus, the fault codes in the list are not
necessarily displayed in order of occurrence.Fault codes are
retained through loss of power.The fault code list in memory
can be cleared by shorting the J4 Test pins briefly when the
compressor is off. NOTE: This action may also have other
consequences - See Delay Override on page 7.
Instrumentation
The18SEERiQDrivesplitheatpumpincludesinstrumentation
as listed in Table 7. All items listed are connected to the
interface board except for the high pressure switch. Refer
to Figures 2, 7, 8, and 9. The five temperature sensors are
color coded so that the color of the wire insulation matches
the color of the connector base on the left side of the circuit
board.All temperature sensors are 10k ohm thermistors.The
resistances of these sensors (when disconnected from the
interfaceboard) maybe checkedagainst Figure 10 (page15)
for troubleshootingpurposes.Figure 10 shows thethermistor
resistance-temperature curve broken into two parts for ease
of use.
FUNCTION TYPE CONNECTION
High Pressure
Switch Opens 650 ±15 psig, recloses 460 ±15 psig See Figures 8 & 9
LowPressure
Switch Opens 20 ±5 psig, recloses 35 ±5 psig IFB*LP1-LP2
Ambient
Air Temp Thermistor10KΩ@ 25° C (Fig. 10) IFB*“OUTDOORTEMP” (BLK)
Compressor
Discharge Temp Thermistor10KΩ@ 25° C (Fig. 10) IFB*“DISCHARGETEMP” (RED)
Coil Defrost
Temp Thermistor10KΩ@ 25° C (Fig. 10) IFB*“COIL#1TEMP” (WHT)
Coil Saturation
Temp Thermistor10KΩ@ 25° C (Fig. 10) IFB*“COIL#2TEMP” (YEL)
Suction
Temp Thermistor10KΩ@ 25° C (Fig. 10) IFB*“SUCTIONTEMP” (BLU)
*IFB=Interface Board
Table 7. Instrumentation List

9
FIGURES & CHARTS
Figure2.HeatPumpControlPanel(CoverRemoved)
Inverter
(blackplasticcase)
Interface
Board
LowVoltage
Compartment
Contactor
}
}

10
Figure4.LowVoltageCompartmentfor
ControlWiring
Figure 3. PowerWiringTerminals
Figure5.ServiceValves
VaporLine
ServiceValve
Liquid Line
ServiceValve
Wire Entry
Ground Lug
Contactor

11
Figure 6. Charging Charts
200
250
300
350
400
450
500
60 70 80 90 100110 120
Liquid Line Pressure (psig)
Cooling Charging Chart
(Outdoor Temperature above 60° F)
Liquid Line Temperature (° F)
250
300
350
400
450
60 65 70 75 80 85 90 95 100
Heating Charging Chart
5 TON
Remove refrigerant
if above the curve.
Add refrigerant if
below the curve.
(Outdoor Temperature below 60° F, Indoor Temperature 75° F)
Liquid Line Pressure (psig)
Liquid Line Temperature (° F)
Remove refrigerant
if above the curve.
Add refrigerant if
below the curve.
4 TON
3 TON
2 TON

12
Figure 7. Interface Board in Control Panel
Test Pins
DefrostTermination
Selection
2-Character
Display

13
Figure8.WiringDiagram(2-4TonModels)
WIRING DIAGRAM
FIELD WIRING
LEGEND:
LOW VOLTAGE
HIGH VOLTAGE
Line Voltage 208/230VA
Cz
H06/esahP1pmuPtaeHtilpSnoT4,3,2-GB4TF/GB4HSP
NOTES:
1. Disconnect all power before servicing. 2. For supply connections use copper conductors only. 3. Not suitable on systems that exceed 150 volts to ground. 4. For replacement wires use conductors suitable for 105 deg.C. 5. For ampacities and overcurrent protection, see unit rating plate.
1. Couper le courant avant de faire letretien. 2. Employez uniquement des conducteurs en cuivre. 3. Ne convient pas aux installations de plus de 150 volt a la terre.
6. Connect to 24 vac/60va/class 2 circuit. See furnace/air handler installation instructions for control circuit and optional relay/ transformer kits. 7. Ferrite chokes are shown by an ellipse enclosing wires. The number of turns per wire through the choke is shown by , for example.
2X
711200A
(Replaces 7112000)
04/12
HIGH
PRESSURE
SWITCH
L2 L1 ACN ACL PE U V W
+12V
GND
DX+
DX-
INTERFACE BOARD
REV VLV
OUTDOOR TEMP
2#PMETLIOC1#PMETLIOC
SUCTION TEMP SUCTION PRESSUREEXV DRIVER LPS
DISCHARGE TEMP
OUTDOOR
TEMP
SUCTION
TEMP
DISCHARGE
TEMP
COIL
TEMP #2 LOW PRESSURE
SWITCH
PWM FAN
CONTROL
COMPRESSOR
TO 208/230-1-60 POWER SUPPLY
REACTOR GND
AC OUT AC
IN
32A
POWER LINE
FILTER
CONTACTOR
NL
L
N
R C Y1 Y2 O W2 L
L2
ON
LOW
HI
PWM
GND
FLT
RPM
WV
U
BLACK
BLUE
RED
YELLOW
BLUE
RED
WHITE
ETIHW
T2 T1
L2 L1
BLACK
YELLOW
BLACK
COIL
TEMP #1
(DEFROST)
WHITE
REVERSING
VALVE
THERMOSTAT
CONTROL
POWER
24VAC
CRANKCASE
HEATER
BLACK
BLACK
BLACK
BLACK
BROWN
RED
BLACK
YELLOW
RED
BLACK
1 2
3
4 5 6 7
24 VAC
DX+
DX-
2134
R C
Y1
Y/Y2
O
W2
L
WU V
COMPRESSOR SHELL (TOP VIEW)
OUTDOOR FAN MOTOR
8X
2X
8X
GREEN
BLACK
BROWN
+12V
GND
DX+
DX-
1X
3X
1X
1X 2X 4X 2X
3X
3 2 1
FACTORY
TEST
PLUG
WHITE
RED
YELLOW
BROWN
BLUE
ORANGE
WHITE
BLACK
YELLOW
RED
RED
YELLOW
BLACK
BLACK
WHITE
YELLOW
GREEN
SHIELDING

14
Line Voltage 208/230VA
Cz
H06/esahP1pmuPtaeHtilpSnoT5-GB4TF/GB4HSP
WIRING DIAGRAM
NOTES:
1. Disconnect all power before servicing. 2. For supply connections use copper conductors only. 3. Not suitable on systems that exceed 150 volts to ground. 4. For replacement wires use conductors suitable for 105 deg.C. 5. For ampacities and overcurrent protection, see unit rating plate.
1. Couper le courant avant de faire letretien. 2. Employez uniquement des conducteurs en cuivre. 3. Ne convient pas aux installations de plus de 150 volt a la terre.
6. Connect to 24 vac/60va/class 2 circuit. See furnace/air handler installation instructions for control circuit and optional relay/ transformer kits. 7. Ferrite chokes are shown by an ellipse enclosing wires. The number of turns per wire through the choke is shown by , for example.
2X
FIELD WIRING
LEGEND:
LOW VOLTAGE
HIGH VOLTAGE
711201A
(Replaces 7112010)
04/12
HIGH
PRESSURE
SWITCH
W V U P1 P2 PE ACN ACL L1 L2
+12V
GND
DX+
DX-
INTERFACE BOARD
REV VLV
OUTDOOR TEMP
2#PMETLIOC1#PMETLIOC
SUCTION TEMP SUCTION PRESSUREEXV DRIVERLPS
DISCHARGE TEMP
OUTDOOR
TEMP
SUCTION
TEMP
DISCHARGE
TEMP
COIL
TEMP #2 LOW
PRESSURE
SWITCH OUTDOOR
FAN MOTOR
PWM FAN
CONTROL
COMPRESSOR
TO 208/230-1-60 POWER SUPPLY
REACTOR
GND
W
AC OUT AC
IN
POWER LINE
FILTER CONTACTOR
TERMINAL
BLOCK
RELAY
N L
N L
V
U
R C
Y1
Y/Y2
O
W2
L
R C Y1 Y2 O W2 L
24 VAC
DX+
DX-
GND
+12V
GND
DX+
DX-
L2
ON
LOW
HI
PWM
GND
FLT
RPM
BLACK
BLUE
RED
YELLOW
BLUE
RED
WHITE
ETIHW
T2 T1
L2 L1
BLACK
PTC A1
A2
L1
T1
L2
T2
YELLOW
BLACK
WU V
COMPRESSOR SHELL (TOP VIEW)
COIL
TEMP #1
(DEFROST)
WHITE
REVERSING
VALVE
THERMOSTAT
CONTROL
POWER
24VAC
CRANKCASE
HEATER
BLACK
BLACK
BLACK
BLACK
BROWNRED
BLACK
RED
RED RED
BLACK RED
BLACK
BLUE YELLOW
RED RED
RED RED
1 2
3
4 5 6 7
2134
50A
8X
2X
8X
GREEN
BLACK
BROWN
1X
1X 1X
4X
2X
4X 4X
3 2 1
FACTORY
TEST
PLUG
BLUE
WHITE
RED
YELLOW
BROWN
BLUE
ORANGE
WHITE
BLACK
YELLOW
RED
BLACK
RED
YELLOW
BLACK
WHITE
YELLOW
GREEN
SHIELDING
Figure9.WiringDiagram(5TonModels)

15
70
80
90
100
110
120
130
140
150
160
170
12345678
91
0
Deg F
k Ω
Temperature vs. Resistance for All Thermistors (Part 1)
-10
0
10
20
30
40
50
60
70
80
10 20 30 40 50 60 70 80 90 100
Deg F
Temperature vs. Resistance for All Thermistors (Part 2)
k Ω
Figure 10.Temperature Sensor Resistance Charts

INSTALLATION / PERFORMANCE CHECK LIST
Specifications & illustrations subject to change without notice or incurring obligations.
O’Fallon, MO | Printed in U.S.A. (05/12) 7092300 (NEW)
ELECTRICAL SYSTEM
Electrical connections tight? YES NO
Linevoltagepolaritycorrect? YES NO
RatedVoltage: _____________________________________ VOLTS
L1-L2Volts: _______________________________________ VOLTS
Max. deviation of voltage
fromratedvolts:____________________________________ VOLTS
%Voltimbalance: __________________________________ VOLTS
BlowerMotorHP:__________________________
Has the thermostat been calibrated? YES NO
Is the thermostat level? YES NO
INSTALLATION ADDRESS:
CITY ________________________ STATE ________________
UNITMODEL# ________________________________________
UNITSERIAL# ________________________________________
Unit Installed Minimum clearances per
Figure 1 (page 3)? YES NO
INSTALLER NAME:
CITY _______________________ STATE ________________
REFRIGERATION SYSTEM
Was unit given 24 hr warm up period for
crankcase heaters? YES NO
Stage-1LiquidPressure(highside) ________________________
Stage-1 Suction Pressure (low side)________________________
Hastheowner’sinformationbeenreviewed
with the customer? YES NO
HastheLiteraturePackagebeenleftwith
the unit? YES NO