International comfort products R- 410A User manual

428 01 5110 00 08/01/17
INSTALLATION INSTRUCTIONS
R- 410A Split System Heat Pumps
NXH6
These instructions must be read and understood completely before attempting installation.
IMPORTANT: Effective January 1, 2015, all split system and packaged air conditioners must be installed pursuant to
applicable regional efficiency standards issued by the Department of Energy.
DANGER, WARNING, CAUTION, and
NOTE
The signal words DANGER, WARNING,
CAUTION, and NOTE are used to identify levels of
hazard seriousness. The signal word DANGER is
only used on product labels to signify an immediate
hazard. The signal words WARNING, CAUTION,
and NOTE will be used on product labels and
throughout this manual and other manuals that may
apply to the product.
DANGER - Immediate hazards which will result in
severe personal injury or death.
WARNING - Hazards or unsafe practices which
could result in severe personal injury or death.
CAUTION - Hazards or unsafe practices which
may result in minor personal injury or product or
property damage.
NOTE - Used to highlight suggestions which will
result in enhanced installation, reliability, or
operation.
Signal Words in Manuals
The signal word WARNING is used throughout this
manual in the following manner:
The signal word CAUTION is used throughout this
manual in the following manner:
Signal Words on Product Labeling
Signal words are used in combination with colors
and/or pictures on product labels.
WARNING
Safety Labeling and Signal Words
!
CAUTION
WARNING
!
TABLE OF CONTENTS
Safety Considerations 2...........................
Installation Recommendations 2...................
Installation 2.....................................
Electrical Wiring 6................................
Defrost System 7................................
Start- up Procedure 9.............................
General Sequence of Operation 10.................
R- 410A Quick Reference Guide 11.................
!WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in per-
sonal injury and/or death.
Before installing, modifying, or servicing system,
main electrical disconnect switch must be in the
OFF position. There may be more than 1 discon-
nect switch. Lock out and tag switch with a suit-
able warning label.
!CAUTION
CUT HAZARD
Failure to follow this caution may result in per-
sonal injury
Sheet metal parts may have sharp edges or burrs.
Use care and wear appropriate protective clothing
and gloves when handling parts.

INSTALLATION INSTRUCTIONS R- 410A Split System Heat Pumps
2428 01 5110 00
Specifications subject to change without notice.
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service,
maintenance, or use can cause explosion, fire, electrical
shock, or other conditions which may cause death, personal
injury, or property damage. Consult a qualified installer,
service agency, or your distributor or branch for information or
assistance. The qualified installer or agency must use
factory- authorized kits or accessories when modifying this
product. Refer to the individual instructions packaged with
the kits or accessories when installing.
Follow all safety codes. Wear safety glasses, protective
clothing, and work gloves. Use quenching cloth for brazing
operations. Have fire extinguisher available. Read these
instructions thoroughly and follow all warnings or cautions
included in literature and attached to the unit. Consult local
building codes and current editions of the National Electrical
Code ( NEC ) NFPA 70. In Canada, refer to current editions
of the Canadian electrical code CSA 22.1.
Recognize safety information. This is the safety- alert symbol
!!When you see this symbol on the unit and in instructions
or manuals, be alert to the potential for personal injury.
Understand these signal words; DANGER, WARNING, and
CAUTION. These words are used with the safety- alert
symbol. DANGER identifies the most serious hazards which
will result in severe personal injury or death. WARNING
signifies hazards which could result in personal injury or
death. CAUTION is used to identify unsafe practices which
would result in minor personal injury or product and property
damage. NOTE is used to highlight suggestions which will
result in enhanced installation, reliability, or operation.
INSTALLATION RECOMMENDATIONS
NOTE: In some cases noise in the living area has been
traced to gas pulsations from improper installation of
equipment.
1. Locate unit away from windows, patios, decks, etc.
where unit operation sound may disturb customer.
2. Ensure that vapor and liquid tube diameters are
appropriate for unit capacity.
3. Run refrigerant tubes as directly as possible by
avoiding unnecessary turns and bends.
4. Leave some slack between structure and unit to
absorb vibration.
5. When passing refrigerant tubes through the wall, seal
opening with RTV or other pliable silicon- based caulk.
(See Fig. 1.)
6. Avoid direct tubing contact with water pipes, duct work,
floor joists, wall studs, floors, and walls.
7. Do not suspend refrigerant tubing from joists and studs
with a rigid wire or strap which comes in direct contact
with tubing.(See Fig. 1.)
8. Ensure that tubing insulation is pliable and completely
surrounds vapor tube.
9. When necessary, use hanger straps which are 1 in.
(25.4 mm) wide and conform to shape of tubing
insulation. (See Fig. 1.)
10. Isolate hanger straps from insulation by using metal
sleeves bent to conform to shape of insulation.
INSULATION
SUCTION TUBE
LIQUID TUBE
OUTDOOR WALL INDOOR WALL
LIQUID TUBE
SUCTION TUBE
INSULATION
CAULK
HANGER STRAP
(AROUND SUCTION
TUBE ONLY)
JOIST
1” (25.4 mm)
MIN
THROUGH THE WALL
SUSPENSION
A07588
Fig. 1 - Connecting Tube Installation
When outdoor unit is connected to factory- approved indoor
unit, outdoor unit contains system refrigerant charge for
operation with AHRI rated indoor unit when connected by 15
ft. (4.57 m) of field- supplied or factory accessory tubing. For
proper unit operation, check refrigerant charge using
charging information located on control box cover and/or in
the Check Charge section of this instruction.
IMPORTANT: Maximum liquid- line size is 3/8- in. OD for all
residential applications including long line.
IMPORTANT: Always install the factory- supplied liquid- line
filter drier. Obtain replacement filter driers from your
distributor or branch.
INSTALLATION
Check Equipment and Job Site
Unpack Unit
Move to final location. Remove carton taking care not to
damage unit.
Inspect Equipment
File claim with shipping company prior to installation if
shipment is damaged or incomplete. Locate unit rating plate
on unit corner panel. It contains information needed to
properly install unit. Check rating plate to be sure unit
matches job specifications.
Install on a Solid, Level Mounting Pad
If conditions or local codes require the unit be attached to
pad, tie down bolts should be used and fastened through
knockouts provided in unit base pan. Refer to unit mounting
pattern in Fig. 2 to determine base pan size and knockout
hole location.
For hurricane tie downs - contact your local distributor for
details and PE (Professional Certification), if required by local
authorities.
On rooftop applications, mount on level platform or frame.
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. Consult local codes governing rooftop
applications.

INSTALLATION INSTRUCTIONS R- 410A Split System Heat Pumps
428 01 5110 00 3
Specifications subject to change without notice.
Roof mounted units exposed to winds may require wind
baffles. Consult the Low- Ambient pressure switch installation
instructions for wind baffle construction.
NOTE: Unit must be level 2 degrees [3/8 inch rise or fall per
foot of run (10mm rise or fall per 305 mm of run)] or compressor
may not function properly.
Clearance Requirements
When installing, allow sufficient space for airflow clearance,
wiring, refrigerant piping, and service. Allow 24 in. (610 mm)
clearance to service end of unit and 48 in. (1219.2 mm)
above unit. For proper airflow, a 6 in. (152.4 mm) clearance
on one side of unit and 12 in. (304.8 mm) on all remaining
sides must be maintained. Maintain a distance of 24 in.
(609.6 mm) between units or 18 in. (457.2 mm) if no
overhang within 12 ft. (3.66m). Position so water, snow, or ice
from roof or eaves cannot fall directly on unit.
3/8–in. (9.53 mm) Dia.
Tiedown Knockouts in
Basepan(2) Places
View From Top
UNIT BASE PAN
Dimension in. (mm)
TIEDOWN KNOCKOUT LOCATIONS in. (mm)
A B C
31–1/2 X 31–1/2
(800 X 800) 9–1/8 (231.8) 6–9/16 (166.7) 24–11/16 (627.1)
35 X 35
(889 X 889) 9–1/8 (231.8) 6–9/16 (166.7) 28–7/16 (722.3)
A05177
Fig. 2 - Tiedown Knockout Locations
On rooftop applications, locate unit at least 6 in. (152.4 mm)
above roof surface.
Operating Ambient
The minimum outdoor operating ambient in cooling mode is
55°F (12.78_C) without low ambient cooling enabled, and the
maximum outdoor operating ambient in cooling mode is
125°F (51.67_C). The maximum outdoor operating ambient in
heating mode is 66°F (18.89_C)
Elevate Unit
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Unit must be kept free of an accumulation of water and/or
ice in the basepan.
Elevate unit per local climate and code requirements to
provide clearance above estimated snowfall level and ensure
adequate drainage of unit. If using accessory support feet,
use installation instructions from kit for installation.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
To prevent damage to the unit, ensure that it is located
with the supports such that the unit is stable in all
circumstances including adverse conditions.
Make Piping Connections
!WARNING
PERSONAL INJURY AND ENVIRONMENTAL
HAZARD
Failure to follow this warning could result in personal
injury or death.
Relieve pressure and recover all refrigerant before system
repair or final unit disposal.
Use all service ports and open all flow- control devices,
including solenoid valves.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Do not leave system open to atmosphere any longer than
minimum required for installation. POE oil in compressor is
extremely susceptible to moisture absorption. Always keep
ends of tubing sealed during installation.
If ANY refrigerant tubing is buried, provide a 6 in. (152.4
mm) vertical rise at service valve. Refrigerant tubing
lengths up to 36 in. (914.4 mm) may be buried without
further special consideration. Do not bury lines more than
36 in. (914.4 mm).
!WARNING
PERSONAL DAMAGE HAZARD
Failure to follow this warning may result in equipment
damage or improper operation.
To prevent damage to unit or service valves, observe the
following:
SUse a brazing shield.
SWrap service valves with wet cloth or use a heat sink
material.
Outdoor units may be connected to indoor section using
accessory tubing package or field- supplied refrigerant grade
tubing of correct size and condition. For tubing requirements
beyond 80 ft/24.38 m, substantial capacity and performance
losses can occur. Following the recommendations in the
Long Line Applications Guideline will reduce these losses.
Refer to Table 1 for accessory requirements. Refer to Table 2
for field tubing diameters.
If refrigerant tubes or indoor coil are exposed to atmosphere,
they must be evacuated to 500 microns to eliminate
contamination and moisture in the system.

INSTALLATION INSTRUCTIONS R- 410A Split System Heat Pumps
4428 01 5110 00
Specifications subject to change without notice.
Table 1 - Accessory Usage
Accessory
REQUIRED FOR LOW–AMBIENT
COOLING APPLICATIONS
(Below 55F / 12.8C)
REQUIRED FOR
LONG LINE APPLICATIONS*
REQUIRED FOR
SEA COAST APPLICATIONS
(Within 2 miles / 3.22 km)
Accumulator Standard Standard Standard
Compressor Start Assist Capacitor and
Relay Ye s Ye s No
Crankcase Heater Ye s Ye s No
Evaporator Freeze Thermostat Ye s No No
Isolation Relay Ye s No No
Liquid Line Solenoid Valve No See Long–Line Application Guideline No
Low Ambient Switch Ye s }No No
Support Feet Recommended No Recommended
* For tubing line sets between 80 and 200 ft. (24.38 and 60.96 m) and/or 20 ft. (6.09 m) vertical differential, refer to Residential Piping and Longline Guideline.
}In units equipped with ECM OD motor, motor needs to be replaced per unit accessory guide to work properly. This motor kit comes with a new defrost board
that also needs to be installed. Unit will not meet AHRI rated efficiency once motor and defrost board are replaced to use this accessory.
Table 2 - Refrigerant Connections and Recommended Liquid and Vapor Tube Diameters (In.)
UNIT SIZE
LIQUID
RATED VAPOR
up to 80 ft. (24.38 m)*
Connection Diameter Tube Diameter Connection Diameter Rated Tube Diameter
18, 24 3/8 3/8 5/8 5/8
30, 36 3/8 3/8 3/4 3/4
42, 48 3/8 3/8 7/8 7/8
60 3/8 3/8 7/8 1- 1/8
* Units are rated with 25 ft. (7.6 m) of lineset. See Specification sheet for performance data when using different size and length linesets.
Notes:
1. Do not apply capillary tube or fixed orifice indoor coils to these units.
2. For Tubing Set lengths between 80 and 200 ft. (24.38 and 60.96 m) horizontal or 35 ft. (10.7 m) vertical differential 250 ft. (76.2 m) Total Equivalent Length),
refer to the Long Line Applications Guideline.
Outdoor Unit Connected to Factory Approved
Indoor Unit
These outdoor units are carefully evaluated and listed with
specific indoor coils for proper system performance.
Install Adapter Tube (36, 42, and 60 Units Only)
1. Remove plastic retainer holding outdoor piston in liquid
service valve.
2. Check outdoor piston size with matching number listed
on unit rating plate.
3. Locate plastic bag taped to unit containing adapter
tube.
4. Remove Teflonseal from bag and install on open
end of liquid service valve. (See Fig. 3.)
5. Remove adapter tube from bag and connect threaded
nut to liquid service valve. Tighten nut finger- tight and
then with wrench an additional 1/2 turn (15 ft- lb). DO
NOT OVER TIGHTEN!
PISTON BODY
LIQUID SERVICE VALVE
PISTON
PLASTIC WASHER
ADAPTER TUBE
BRASS NUT
Fig. 3 - Liquid Service Valve
NOTE: 18, 24, 30, and 48 units have an OD TXV installed
for heating expansion and do not require a piston. These
units have a standard AC liquid service valve.
Refrigerant Tubing and Sweat Connections
Connect vapor tube to fitting on outdoor unit vapor service
valves (see Table 2.) Connect liquid tubing to adapter tube
on liquid service valve (36, 42, 60) or to liquid service valve
(18, 24, 30, 48). Use refrigerant grade tubing.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Service valves must be wrapped in a heat- sinking
material such as a wet cloth while brazing.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Installation of filter drier in liquid line is required.
Install Liquid Line Filter Drier Indoor
Refer to Fig. 4 and install filter drier as follows:
1. Braze 5 in. (127 mm) liquid tube to the indoor coil.
2. Wrap filter drier with damp cloth.
3. Braze filter drier to 5 in. (127 mm) liquid tube from
step 1.
4. Connect and braze liquid refrigerant tube to the filter
drier.

INSTALLATION INSTRUCTIONS R- 410A Split System Heat Pumps
428 01 5110 00 5
Specifications subject to change without notice.
Fig. 4 - Liquid Line Filter Drier
Leak Testing
Leak test all joints; indoors, outdoors, and refrigerant tubing.
Evacuate Refrigerant Tubing and Indoor Coil
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Never use the system compressor as a vacuum pump.
Refrigerant tubes and indoor coil should be evacuated using
the recommended deep vacuum method of 500 microns. An
alternate triple evacuation method may be used. See triple
evacuation method in Service Manual.
IMPORTANT: Always break a vacuum with dry nitrogen.
Deep Vacuum Method
The deep vacuum method requires a vacuum pump capable
of pulling a vacuum of 500 microns and a vacuum gage
capable of accurately measuring this vacuum depth. The
deep vacuum method is the most positive way of assuring a
system is free of air and liquid water. (See Fig.5)
500
MINUTES
01234567
1000
1500
LEAK IN
SYSTEM
VACUUM TIGH
T
TOO WET
TIGHT
DRY SYSTEM
2000
MICRONS
2500
3000
3500
4000
4500
5000
Fig. 5 - Deep Vacuum Graph
Final Tubing Check
IMPORTANT: Check to be certain factory tubing on both
indoor and outdoor unit has not shifted during shipment.
Ensure tubes are not rubbing against each other or any
sheet metal. Pay close attention to feeder tubes, making sure
wire ties on feeder tubes are secure and tight, as applicable.
ELECTRICAL WIRING
!WARNING
ELECTRICAL SHOCK HAZARD
Failure to turn off the main (remote) electrical dis-
connect device could result in personal injury or
death.
Before installing, modifying or servicing system,
turn OFF the main (remote) electrical disconnect
device. There may be more than one disconnect
device.
Supply voltage must be 208/230 volts (197 volt minimum
to 253 volts maximum) 60 Hz single phase.
Outdoor units are approved for use with copper
conductors only. Do not use aluminum wire.
Refer to unit rating plate for minimum circuit ampacity
and circuit protection requirements.
Grounding
Permanently ground unit in accordance with the National
Electrical Code and local codes or ordinances. Use a
copper conductor of the correct size from the grounding
lug in control box to a grounded connection in the service
panel or a properly driven and electrically grounded
ground rod.
Wiring Connections
Make all outdoor electrical supply (Line Voltage)
connections with raintight conduit and fittings. Most
codes require a disconnect switch outdoors within sight
of the unit. Consult local codes for special requirements.
Route electrical supply (Line Voltage) wiring through
knockout hole in bottom of Control Box. Connect wires to
Contactor and Ground Lug according to Wiring Diagram
on unit. Refer to Figure 6.
Route thermostat wiring through rubber grommet in
bottom of Control Box. Low voltage lead wires are
provided in the control box for connection to thermostat
wires (use wire nuts). Refer to Wiring Diagram on unit
and Figure 7 for low voltage wiring examples.
NOTE: Use No. 18 AWG (American Wire Gage)
color- coded, insulated (35 °C minimum) wire. If
thermostat is located more than 100 feet (30.5 m) from
unit as measured along the control voltage wires, use
No. 16 AWG color- coded wires to avoid excessive
voltage drop.

INSTALLATION INSTRUCTIONS R- 410A Split System Heat Pumps
6428 01 5110 00
Specifications subject to change without notice.
DISCONNECT
PER NEC AND/OR
LOCAL CODES
CONTACTOR
GROUND
LUG
FIELD GROUND
WIRING
FIELD POWER
WIRING
11
23 or 13
L1
L2
Fig. 6 - Electrical Supply (Line Voltage) Connections
LEGEND
24 - V FACTORY WIRING
24 - V FIELD WIRING
FIELD SPLICE CONNECTION
OUTDOOR THERMOSTAT
EMERGENCY HEAT RELAY
SUPPLEMENTAL HEAT RELAY
SHR
EHR
C
W2
L
G
Y
E
O
R
C
W2
L
G
Y
E
O
R
ODT
EHR
ODT
ODT
REMOVE WIRES FROM CRIMP NUT IN INDOOR FAN COIL WHEN INSTALLING OUTDOOR THERMOSTATS.
SYSTEMS WITH ONE OUTDOOR THERMOSTAT
G
R
W3
C
O
R
G
R
W3
C
E
C
W2
Y
W2
O
R
C
W2
Y
W2
C
L
G
Y
E
O
R
SYSTEMS WITHOUT OUTDOOR THERMOSTATS
C
G
R
W2
C
Y
O
R
W2
SUBBASE
THERMOSTAT
CONNECTION
SPLICE
INDOOR
CONNECTION
SPLICE
OUTDOOR
BOARD
DEFROST
SUBBASE
THERMOSTAT
CONNECTION
SPLICE
INDOOR
CONNECTION
SPLICE
OUTDOOR
BOARD
DEFROST
SUBBASE
THERMOSTAT
CONNECTION
SPLICE
INDOOR
CONNECTION
SPLICE
OUTDOOR
BOARD
DEFROST
SYSTEMS WITH TWO OUTDOOR THERMOSTATS
NOTE: WHEN USING OUTDOOR THERMOSTATS, W2MUST BE ENERGIZED WHEN REQUESTING SUPPLEMENTAL HEAT.
W2E
SHR
SHR
Fig. 7 - Typical Thermostat (Control Circuit) Connections

INSTALLATION INSTRUCTIONS R- 410A Split System Heat Pumps
428 01 5110 00 7
Specifications subject to change without notice.
DEFROST SYSTEM
A. DEFROST THERMOSTAT
The defrost thermostat is factory installed on a short tube
stub extending from the coil end plate. Refer to Figure 8
and confirm that the thermostat is securely fastened in
place on the tube stub.
FEEDER TUBE
TUBE STUB
DEFROST
THERMOSTAT
COIL
Fig. 8 - Defrost Thermostat
B. DEFROST CONTROL BOARD
The defrost board is a time/temperature control which
includes a field- selectable time period between defrost
cycles of 30, 60, or 90 minutes (quick- connects located
at board edge, factory set at 60 or 90 minutes).
Defrost mode is identical to cooling mode except that
outdoor- fan motor stops and second- stage heat is
turned on to continue warming conditioned space.
Initially, the defrost cycle timer starts when the contactor
is energized and a 24 VAC signal is present on the T1
terminal. Then the defrost cycle begins when the defrost
thermostat is closed and the cycle timer times out (30,
60, or 90 minutes).
There are two timers involved in the defrost sequence:
Interval Timer – 30, 60, or 90 minutes, selected by
setting the jumper on the defrost board. Timer is only
active during calls for heating. Timer starts when the
defrost thermostat closes 32°F(0°C). Timer stops when
a defrost is initiated by the defrost board or when the
defrost thermostat opens 65°F(18°C).
Defrost Timer – 10 minutes, not adjustable. Timer is
only active while the coil is defrosting. Timer starts when
the defrost board initiates a defrost. Timer stops when
the defrost thermostat opens 65°F(18°C) or after timing
out at 10 minutes (whichever comes first).
SPEEDUP pins are provided on the defrost board to help
in troubleshooting without waiting for timers to expire.
Jumpering the SPEEDUP pins causes any active timer
to run very fast (256 times normal speed). Jumpering the
SPEEDUP pins does not by itself initiate any timers, it
only affects timers that are already running or are already
part of the sequence.
To initiate a forced defrost cycle (test cycle), the defrost
thermostat (Figure 9) must be closed.
There are two ways to verify that the defrost
thermostat is closed:
1. Jumper across the DFT terminals on the defrost
board (Figure 9). With this method, the defrost
thermostat is removed from the circuit, and
operation of the defrost thermostat itself will not be
observed. Skip to #3.
2. Use a volt-meter to confirm there is no voltage across
the DFT leads. 24 volts across the SFT terminals
indicates an OPEN defrost thermostat. Zero volts
across the DFT terminals indicates a CLOSED defrost
thermostat.
With this method, the operation of the defrost
thermostat can be observed during the test. If the
defrost thermostat is confirmed closed, skip to #3.
If the defrost thermostat is open (24 volts across DFT
leads) it may be possible to close the defrost
thermostat by forcing a frost buildup on the outdoor
coil. Follow these steps:
STurn off power to unit.
SFor units with PSC motors, disconnect outdoor
fan-motor lead from the OF2 terminal on control
board; For units with ECM motors, disconnect
outdoor fan- motor lead from the ODF terminal.
(Figure 9). Tape lead to prevent grounding.
SRestart unit in heating mode; wait for
accumulation of frost on outdoor coil. Use
volt-meter to confirm there are zero volts across
the DFT leads (thermostat closed).
STurn off power to unit. Replace outdoor fan-motor
lead to either OF2 or ODF terminal on control
board, depending on type of motor (Figure 9).
Restart the unit in heating mode.
3. With unit running in heating mode and the defrost
thermostat closed, the entire defrost sequence can
be sped up for testing by shorting together the
SPEEDUP pins on the defrost board. Use a
flat-headed screwdriver to short the pins together.
4. Hold the SPEEDUP pins shorted together until the
reversing valve shifts.
SPEEDUP reduces whatever time was left on the
interval timer (30/60/90 minutes). In normal operation
the reversing valve will always shift with the SPEEDUP
pins shorted for between 1 and 21 seconds.
5. After shorting the SPEEDUP pins together as
described in #4, the reversing valve will energize
(shift to AC mode), the outdoor fan will stop, the strip
heat will energize, and the coil will begin to defrost.
There are two options for the defrost test:
a. Remove the short from between the SPEEDUP
pins immediately after the reversing valve shifts,
and the unit will defrost for a shortened period of
time (something less than 10 minutes). The
defrost will stop when the defrost thermostat
opens (reaches 65°F)(18°C) or when the
defrost timer times out (something less than 10
minutes).
b. Leave the SPEEDUP pins shorted together for
more than 2 seconds after the reversing valve
shifts, and the unit will immediately return to
heating operation (#6 below). Continue to leave
the pins shorted together and the sequence
starts over at #4 above.
6. Unit returns to heating mode after defrost sequence.
Reversing valve shifts back, outdoor fan starts up,
and strip heat de-energizes.

INSTALLATION INSTRUCTIONS R- 410A Split System Heat Pumps
8428 01 5110 00
Specifications subject to change without notice.
For units with PSC motors
For units with ECM motors
R8
OF1 K1
O1
R21
C2
R6
H9C1
CUS

R14 R13
D13
R7
C4
C10
JW2
JW1
D3
C16
C7
R28
D6
JW3
C13
R4
R1 R2 R3 R11 R5
R26
D1 D2
D10
A29
R9 D4
C19 C9
C1
OF2
CEBD430524- 01A 5501A
P2
1Y
T1 C C O
DFT
SPEEDUP
P1
1
J1
1
P3
1J2
30 60 90
W1
R20
1
HK32EA001
C17
U1
1
U3
O
R
W2
Y
C
Fig. 9 - Defrost Control Boards

INSTALLATION INSTRUCTIONS R- 410A Split System Heat Pumps
428 01 5110 00 9
Specifications subject to change without notice.
START- UP PROCEDURE
1. Set indoor thermostat selector switch to OFF.
2. Turn ON all electrical disconnect devices.
3. If unit has a crankcase heater, energize the heater
and wait 24 hours before proceeding.
4. Set indoor thermostat at desired temperature. Be
sure setpoint is below indoor ambient temperature
to call for cooling, or above indoor ambient to call
for heating.
5. Set indoor thermostat selector switch to COOL or
HEAT. Operate unit for minimum 15 minutes, then
check the system refrigerant charge.
REFRIGERANT CHARGE
Factory charge amount and desired subcooling are
shown on unit rating plate. Charging method is shown on
information plate inside unit. Additional subcooling may
be required to achieve optimal heating performance
based on installed indoor unit.
For TXV, use subcooling method.
For Piston, use superheat method.
To properly check or adjust charge, conditions must be
favorable for subcooling or superheat charging.
Favorable conditions exist when the outdoor
temperature is between 70_F and 100_F(21_C and
38_C), and the indoor temperature is between 70_F and
80_F(21_C and 27_C). Follow the procedure below.
Unit is factory charged for 15 feet (4.6m) of lineset.
Adjust charge by adding or removing 0.6 oz/ft (17 g/mm)
of 3/8 liquid line above or below 15 feet (4.6 m)
respectively.
For standard refrigerant line lengths 80 feet (24.4m) or
less, allow system to operate in cooling mode at least 15
minutes. If conditions are favorable, check system
charge by super heat method for fixed metering device
and subcooling method for TXV. If any adjustment is
necessary, adjust charge slowly and allow system to
operate for 15 minutes to stabilize before declaring a
properly charged system.
If the indoor temperature is above 80_F(27_C), and the
outdoor temperature is in the favorable range, adjust
system charge by weight based on line length and allow
the indoor temperature to drop to 80_F(27_C) before
attempting to check system charge by subcooling
method as described above.
If the indoor temperature is below 70_F(21_C), or the
outdoor temperature is not in the favorable range, adjust
charge for line set length above or below 15 feet (4.6m)
only. Charge level should then be appropriate for the
system to achieve rated capacity. The charge level could
then be checked at another time when the both indoor
and outdoor temperatures are in a more favorable range.
NOTE: If line length is beyond 80 feet (24.4m) or greater
than 20 feet (6.1m) vertical separation, See Long Line
Guideline for special charging requirements.
COOLING MODE
Units installed with cooling mode TXV require charging
by the subcooling method.
1. Operate unit a minimum of 15 minutes before
checking charge.
2. Measure liquid service valve pressure by
attaching an accurate gage to service port.
3. Measure liquid line temperature by attaching an
accurate thermistor type or electronic
thermometer to liquid line near outdoor coil.
4. Refer to unit rating plate for required subcooling
temperature.
5. Refer to Table 3. Find the point where required
subcooling temperature intersects measured
liquid service valve pressure.
6. To obtain required subcooling temperature at a
specific liquid line pressure, add refrigerant if
liquid line temperature is higher than indicated or
reclaim refrigerant if temperature is lower. Allow a
tolerance of 3_F(1.7_C).
C. HEATING MODE
To check system operation during heating cycle, refer to
the Tech Label on outdoor unit. This chart indicates
whether a correct relationship exists between system
operating pressure and air temperature entering indoor
and outdoor units. If pressure and temperature do not
match on chart, system refrigerant charge may not be
correct. Do not use chart to adjust refrigerant charge.
NOTE: When charging is necessary during heating
season, charge must be weighed in accordance with unit
rating plate 0.6 ounces per foot of an inch liquid line
above or below 15 feet respectively (17g per 305mm of
10mm liquid line above or below 4.6m respectively).

INSTALLATION INSTRUCTIONS R- 410A Split System Heat Pumps
10 428 01 5110 00
Specifications subject to change without notice.
SEQUENCE OF OPERATION
A. COOLING MODE
On a call for cooling, the thermostat makes circuits R- O,
R- Y, and R- G. Circuit R- O energizes reversing valve,
switching it to cooling position. Circuit R- Y energizes
contactor, starting outdoor fan motor and compressor.
Circuit R- G energizes indoor unit blower relay, starting
indoor blower motor.
When thermostat is satisfied, its contacts open,
de- energizing contactor and blower relay. Compressor
and motors stop.
NOTE: If indoor unit is equipped with a time- delay relay
circuit, the blower runs an additional length of time to
increase system efficiency. (Applies to both cooling and
heating modes.)
B. HEATING MODE
On a call for heating, the thermostat makes circuits R- Y
and R- G (circuit R- O is NOT made, and the reversing
valve stays in the de- energized, heating position).
Circuit R- Y energizes contactor, starting outdoor fan
motor and compressor. Circuit R- G energizes indoor
blower relay, starting blower motor. If the room
temperature continues to fall, circuit R- W2 is made
through the second- stage room thermostat bulb. Circuit
R- W2 energizes a sequencer, bringing on the first bank
supplemental electric heat and providing electrical
potential to the second heater sequencer (if used). If
outdoor temperature falls below the setting of the
outdoor thermostat (field- installed option), contacts
close to complete the circuit and bring on the second
bank of supplemental electric heat.
When the thermostat is satisfied, its contacts open,
de- energizing contactor, blower relay, and sequencer.
Compressor, motors, and heaters stop.
Table 3 - Rating Plate (required) Subcooling Temperature °F(°C)
Measured Liquid
Pressure (psig)
°F (°C) °F (°C) °F (°C) °F(° C) F(° C) F (°C)
6 3 8 4 10 612 714 816 9
R- 410A Required Liquid Line Temperature °F(°C)
251 78 26 76 24 74 23 72 22 70 21 68 20
259 80 27 78 26 76 24 74 23 72 22 70 21
266 82 28 80 27 78 26 76 24 74 23 72 22
274 84 29 82 28 80 27 78 26 76 24 74 23
283 86 30 84 29 82 28 80 27 78 26 76 24
291 88 31 86 30 84 29 82 28 80 27 78 26
299 90 32 88 31 86 30 84 29 82 28 80 27
308 92 33 90 32 88 31 86 30 84 29 82 28
317 94 34 92 33 90 32 88 31 86 30 84 29
326 96 36 94 34 92 33 90 32 88 31 86 30
335 98 37 96 36 94 34 92 33 90 32 88 31
345 100 38 98 37 96 36 94 34 92 33 90 32
364 104 40 102 39 100 38 98 37 96 36 94 34
374 106 41 104 40 102 39 100 38 98 37 96 36
384 108 42 106 41 104 40 102 39 100 38 98 37
395 110 43 108 42 106 41 104 40 102 39 100 38
406 112 44 110 43 108 42 106 41 104 40 102 39
416 114 46 112 44 110 43 108 42 106 41 104 40
427 116 47 114 46 112 44 110 43 108 42 106 41
439 118 48 116 47 114 46 112 44 110 43 108 42
450 120 49 118 48 116 47 114 46 112 44 110 43
462 122 50 120 49 118 48 116 47 114 46 112 44
474 124 51 122 50 120 49 118 48 116 47 114 46

INSTALLATION INSTRUCTIONS R- 410A Split System Heat Pumps
428 01 5110 00 11
Specifications subject to change without notice.
R- 410A QUICK REFERENCE GUIDE
R- 410A refrigerant operates at 50% - 70% higher pressures than R- 22. Be sure that servicing equipment and
replacement components are designed to operate with R- 410A.
R- 410A refrigerant cylinders are rose colored.
Recovery cylinder service pressure rating must be 400 psig, DOT 4BA400 or DOT BW400.
R- 410A systems should be charged with liquid refrigerant. Use a commercial type metering device in the
manifold hose.
Manifold sets should be 750 psig high- side and 200 psig low- side with 520 psig low- side retard.
Use hoses with 750 psig service pressure rating.
Leak detectors should be designed to detect HFC refrigerant.
R- 410A, as with other HFC refrigerants, is only compatible with POE oils.
Vacuum pumps will not remove moisture from oil.
Do not use liquid line filter- driers with rated working pressures less than 600 psig.
Do not install a suction line filter- drier in liquid line.
POE oils absorb moisture rapidly. Do not expose oil to atmosphere.
POE oils may cause damage to certain plastics and roofing materials.
Wrap all filter- driers and service valves with wet cloth when brazing.
A liquid line filter- drier is required on every unit.
DonotusewithanR-22TXV.
If indoor unit is equipped with an R- 22 TXV, it must be changed to an R- 410A TXV.
Never open system to atmosphere while it is under a vacuum.
When system must be opened for service, break vacuum with dry nitrogen and replace all filter- driers.
Do not vent R- 410A into the atmosphere.
Do not use capillary tube indoor coils.
Observe all WARNINGS,CAUTIONS, NOTES, and bold text.
Copyright 2017 International Comfort Products
Lewisburg, TN 37091 USA