Armstrong Air 4SHP16LS Series User manual

506860-03 Issue 1827 Page 1 of 29
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INSTALLATION INSTRUCTIONS
4SHP16LS SERIES
Split System Heat Pump
*506860-03*
*506860-03*
Manufactured By
Allied Air Enterprises LLC
A Lennox International, Inc. Company
215 Metropolitan Drive
West Columbia, SC 29170
This manual must be left with the homeowner for future reference.
This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in
manuals, be alert to the potential for personal injury or death.
The equipment covered in this manual is to be installed
by trained and experienced service and installation
technicians. Improper installation, modication, service,
or use can cause electrical shock, re, explosion, or
other conditions, which may cause personal injury,
death, or property damage. Use appropriate safety gear,
including safety glasses and gloves, when installing this
equipment.
WARNING
Risk of electrical shock. Disconnect all remote power
supplies before installing or servicing any portion of the
system. Failure to disconnect power supplies can result
in property damage, personal injury, or death.
WARNING
Installation and servicing of air conditioning equipment
can be hazardous due to internal refrigerant pressure
and live electrical components. Only trained and
qualied service personnel should install or service
this equipment. Installation and service performed by
unqualied persons can result in property damage,
personal injury, or death.
WARNING
Sharp metal edges can cause injury. When installing
the unit, use care to avoid sharp edges.
WARNING
Table of Contents
Installation ...................................................................2
Electrical Wiring...........................................................3
Start-Up .....................................................................14
Operation...................................................................16
7-Segment Alert and System Status Codes ..............18
Maintenance..............................................................24
Homeowner Information ............................................25
Wiring Diagrams........................................................28

506860-03Issue 1827Page 2 of 29
Installation
General
Read this entire instruction manual, as well as the
instructions supplied in separate equipment, before
starting the installation. Observe and follow all warnings,
cautions, instructional labels, and tags. Failure to comply
with these instructions could result in an unsafe condition
and/or premature component failure.
These instructions are intended as a general guide only
for use by qualied personnel and do not supersede any
national or local codes in any way. The installation must
comply with all provincial, state, and local codes as well as
the National Electrical Code (U.S.) or Canadian Electrical
Code (Canada). Compliance should be determined prior
to installation.
This condensing unit uses R410A, which is an ozone-
friendly HFC refrigerant. The unit must be installed with a
matching indoor coil and line set. A lter drier approved for
use with R410A is installed in the unit.
IMPORTANT: This product has been designed and
manufactured to meet ENERGY STAR criteria for energy
efciency when matched with appropriate coil components.
However, proper refrigerant charge and proper air ow are
critical to achieve rated capacity and efciency. Installation
of this product should follow the manufacturer’s refrigerant
charging and air ow instructions. Failure to conrm proper
charge and airow may reduce energy efciency and
shorten equipment life.
When servicing or repairing HVAC components, ensure
the fasteners are appropriately tightened. Table 1 shows
torque values for fasteners.
Table 1. Torque Table
Fastener Torque
Stem Caps 8 ft. lbs.
Service Port Caps 8 ft. lbs.
Sheet Metal Screws 16 in. lbs.
#8 Machine Screws 16 in. lbs.
#10 Machine Screws 28 in. lbs.
Compressor Bolts 90 in. lbs.
Inspection of Shipment
Upon receipt of equipment, carefully inspect it for possible
shipping damage. If damage is found, it should be noted
on the carrier’s freight bill. Take special care to examine
the unit inside the carton if the carton is damaged. Any
concealed damage discovered should be reported to the
last carrier immediately, preferably in writing, and should
include a request for inspection by the carrier’s agent.
If any damages are discovered and reported to the carrier
DO NOT INSTALL THE UNIT, as claim may be denied.
Check the unit rating plate to conrm specications are as
ordered.
Location of Unit
Outdoor units operate under a wide range of weather
conditions; therefore, multiple factors must be considered
when positioning the unit. The unit must be positioned
to give adequate clearances for sufcient airow and
servicing.
Refer to Figure 1 for installation clearances.
• Place a sound-absorbing material, such as Isomode,
under the unit if it will be installed in a location or
position that will transmit sound or vibration to the
living area or adjacent buildings.
Figure 1. Installation Clearances
* A service clearance of 30” must be maintained on one of the
sides adjacent to the control box. Clearance to one of the other
three sides must be 36”. Clearance to one of the remaining two
sides may be 12” and the nal side may be 6”.
A clearance of 24” must be maintained between units.
48” clearance required on top of unit. Maximum soft overhang is
36”.
• Install the unit high enough above the ground or roof to
allow adequate drainage of defrost water and prevent
ice buildup.
• In heavy snow areas, do not locate the unit where
drifting snow will occur. The unit base should be
elevated above the depth of average snows.
NOTE: Elevation of the unit may be accomplished
by construction a frame using suitable materials. If a
support frame is constructed, it must not block drain
holes in unit base.

506860-03 Issue 1827 Page 3 of 29
• When installed in areas where low ambient
temperatures exist, locate unit so winter prevailing
winds do not blow directly into outdoor coil.
• Locate unit away from overhanging roof lines, which
would allow water or ice to drop on, or in front of, coil
or into unit.
Slab Mounting
When installing a unit at grade level, install on slab high
enough above grade so that water from higher ground will
not collect around the unit (see Figure 2). Slab should have
a slope tolerance away from the building of 2° or 2” per 5’.
This will prevent ice from building up under the unit during
a defrost cycle. Refer to following roof mounting section
for barrier construction if unit must face prevailing winter
winds.
Figure 2. Slab Mounting
Discharge Air
Mounting Slab
Ground Level
Building
Structure
Roof Mounting
Install unit at a minimum of 6” above surface of the roof
to avoid ice buildup around the unit. Locate the unit
above a load bearing wall or area of the roof that can
adequately support the unit. Consult local codes for rooftop
applications.
If unit coil cannot be mounted away from prevailing winter
winds, a wind barrier should be constructed (see Figure 3).
Size the barrier at least the same height and width as the
outdoor unit. Mount barrier 24” from the sides of the unit in
the direction of the prevailing winds.
Figure 3.
Electrical Wiring
All eld wiring must be done in accordance with the National
Electrical Code (NEC) recommendations, Canadian
Electrical Code (CEC) and CSA Standards, or local codes,
where applicable.
Refer to the furnace or blower coil installation instructions
for additional wiring application diagrams and refer to unit
rating plate for minimum circuit ampacity and maximum
overcurrent protection size.
Unit must be grounded in accordance with national and
local codes. Failure to ground unit properly can result in
personal injury or death.
WARNING
Line voltage is present at all components when unit is
not in operation on units with single pole contactors.
Disconnect all remote electric power supplies before
opening access panel. Unit may have multiple power
supplies. Failure to disconnect all power supplies could
result in personal injury or death.
WARNING

506860-03Issue 1827Page 4 of 29
Figure 4. Typical Field Wiring Diagram
Non-Communicating
1. Install line voltage power supply to unit from a properly
sized disconnect switch. Any excess high voltage eld
wiring should be trimmed or secured away from the
low voltage eld wiring.
2. Ground unit at unit disconnect switch or to an earth
ground. To facilitate conduit, a hole is in the bottom
of the control box. Connect conduit to the control box
using a proper conduit tting. Units are approved for
use only with copper conductors. 24V Class II circuit
connections are made in the low voltage junction box.
Refer to Figure 4 for high voltage eld wiring diagram.
A complete unit wiring diagram is located inside the
unit control box cover and in the back of this document.
3. Install room thermostat on an inside wall that is not
subject to drafts, direct sunshine, or other heat
sources.
4. Install low voltage wiring from outdoor to indoor
unit and from thermostat to indoor unit. (See wiring
diagrams beginning on Page 28.)
5. Do not bundle any excess 24V control wire inside
control box. Run control wire through installed wire tie
and tighten wire tie to provide low voltage strain relief
and to maintain separation of eld-installed low and
high voltage circuits.
Figure 5. Non-Communicating Thermostat
Designations
NOTE: Some connections may not apply. Refer to specic
thermostat and indoor unit.
Field Wiring and Routing - Communicating
Controls
Maximum length of wiring (18 gauge) for all connections
on the RSBus is 1500 feet (457 meters). Wires should
be color coded, with a temperature rating of 95ºF (35ºC)
minimum, and solid core (Class II Rated Wiring). All low
voltage wiring must be connected through the low voltage
grommet in the control box.

506860-03 Issue 1827 Page 5 of 29
Figure 6.
Comfort SyncTM Thermostat with
Comfort SyncTM-enabled Furnace and
Non-Communicating Outdoor Unit
NON-COMMUNICATING
OUTDOOR AIR
CONDITIONING UNIT -
1OR 2 STAGE
OPTIONAL
OUTDOOR
AIR SENSOR
OPTIONAL
DISCHARGE
AIR SENSOR OPTIONAL
DISCHARGE
AIR SENSOR
Indoor Control
Outdoor Unit
Connect single wire
to terminal C
NOTE: On communicating systems, extra wires must terminate on the indoor “C” Comfort SyncTM
terminal strip (RSBus). Use an additional wire to connect all unused wires to “C” terminal on the indoor
control ONLY.
Comfort SyncTM
Thermostat
Connect single wire
to terminal C
2 STG. ONLY
LSOM ONLY
Comfort SyncTM Thermostat with
Comfort SyncTM-enabled Furnace and
Comfort SyncTM-enabled Outdoor Unit
Comfort SyncTM-
Enabled
Furnace
Comfort SyncTM
Thermostat
INDOOR EQUIPMENT
OUTDOOR EQUIPMENT
CLIP ON-BOARD LINK
W915 (Y1 TO Y2) FOR
TWO-STAGE OPERATION
Comfort SyncTM-
Enabled
Furnace
Comfort SyncTM
Thermostat
Comfort SyncTM-Enabled
OUTDOOR AIR CONDITIONING
OR HEAT PUMP UNIT
INDOOR EQUIPMENT
OUTDOOR EQUIPMENT
All unused wires
All unused wires
OPTIONAL
OUTDOOR
AIR SENSOR

506860-03Issue 1827Page 6 of 29
Placement
Be aware that some localities are adopting sound
ordinances based on how noisy the unit is at the neighbor’s
home, not at the original installation. Install the unit as far
as possible from the property line. When possible, do not
install the unit directly outside a bedroom window. Glass
has a very high level of sound transmission. Figure 7
shows how to place the outdoor unit and line set to reduce
line set vibration.
Line Set Isolation
Illustrations on Page 7 and Page 8 demonstrate
procedures that ensure proper refrigerant line set isolation.
Figure 8 shows how to install line sets on horizontal runs.
Figure 9 shows how to make a transition from horizontal to
vertical. Figure 10 shows how to install line sets on vertical
runs.
Table 2. Refrigerant Line Set Diameters (in.)
Model Liquid Line Suction Line
24 3/8 3/4
36 3/8 7/8
48 3/8 7/8
60 3/8 1-1/8
For installations exceeding 50’, refer to long line set guide lines
Brazing Connection Procedure
1. Cut ends of refrigerant lines square (free from nicks or
dents). Debur the ends. The pipe must remain round;
do not pinch end of line.
2. Before making line set connections, use dry nitrogen
to purge the refrigerant piping. This will help to prevent
oxidation and the introduction of moisture into the
system.
3. Use silver alloy brazing rods (5% or 6% silver alloy
for copper-to-copper brazing or 45% silver alloy for
copper-to-brass or copper-to-steel brazing) that are
rated for use with R410A refrigerant.
4. Remove the Schrader core assemblies before brazing
to protect them from damage due to extreme heat.
Replace the cores when brazing is complete.
5. Remove light maroon washers from service valves
and shield light maroon stickers to protect them during
brazing. Wrap a wet cloth around the valve body and
copper tube stub to protect it from heat damage.
6. Braze the line set to the service valve. Quench the
joints with water or a wet cloth to prevent heat damage
to the valve core and opening port. The tube end must
stay bottomed in the tting during nal assembly to
ensure proper seating, sealing, and rigidity.
7. Install the thermal expansion valve, which is sold
separately and which is approved for use with R410A
refrigerant, in the liquid line at the indoor coil (see the
Refrigerant Metering Device section).
Figure 7.
Refrigerant Piping
If the unit is being installed with a new indoor coil and line
set, the refrigerant connections should be made as outlined
in this section. If an existing line set and/or indoor coil will
be used to complete the system, refer to this section as
well as the section that follows, entitled “Flushing Existing
Line Set and Indoor Coil.”
If this unit is being matched with an approved line set
or indoor coil that was previously charged with R-22
refrigerant, the line set and coil must be ushed prior to
installation. If the unit is being used with an existing indoor
coil that was equipped with a liquid line that served as a
metering device (RFCI), the liquid line must be replaced
prior to the installation of the unit.
Field refrigerant piping consists of liquid and suction lines
from the outdoor unit (sweat connections) to the indoor coil
(are or sweat connections).
Select line set diameters from Table 2 to ensure that oil
returns to the compressor. Size vertical suction riser
to maintain minimum velocity at minimum capacity.
Recommended line length is 50’ or less. If more than 50’
line set is required, refer to long line set guide lines. Table
2 shows the diameters for line sets up to 100’, although
vertical lift applications and trapping requirements need to
be reviewed for line sets over 50’; refer to long line set
guide lines

506860-03 Issue 1827 Page 7 of 29
To hang line set from joist or rafter,
use either metal strapping material
or anchored heavy nylon wire ties.
Strapping Material
(around vapor line only)
8’
8’
Tape or Wire Tie
Strap the vapor line to the joist or rafter
at 8intervals then strap the liquid line
to the vapor line.
’
Floor Joist or
Roof Rafter
Metal Sleeve
Floor Joist or Roof Rafter
Tape or Wire Tie
Wire Tie
(around vapor line only)
Figure 8. Refrigerant Line Sets: Installing Horizontal Runs
Installing Refrigerant Line
During the installation of an air conditioning system, it is
important to properly isolate the refrigerant line to prevent
unnecessary vibration. Line set contact with the structure
(wall, ceiling, or oor) may cause objectionable noise when
vibration is translated into sound. As a result, more energy
or vibration can be expected. Close attention to line set
isolation must be observed.
If ANY refrigerant tubing is required to be buried by state
or local codes, provide a 6 inch vertical rise at service
valve.
CAUTION
When ushing existing line set and/or indoor coil, be
sure to empty all existing traps. Residual mineral oil can
act as an insulator, preventing proper heat transfer. It
can also clog the thermal expansion valve, reducing
system performance and capacity. Failure to properly
ush system as explained in these instructions will void
warranty.
CAUTION

506860-03Issue 1827Page 8 of 29
Anchored
Heavy Nylon
Wire Tie
Wall
Stud
Metal Sleeve Vapor Line Wrapped
in Armaflex
–
Liquid Line
Wall
Stud
Automotive
Muffler-Type
Hanger
Strap Liquid
Line to Vapor
Line
Metal Sleeve Vapor Line Wrapped
in Armaflex
–
Liquid Line
Strap Liquid
Line to Vapor
Line
Figure 9. Refrigerant Line Sets: Transition from Horizontal to Vertical
Figure 10. Refrigerant Line Sets: Installing Vertical Runs (new construction shown)
Outside Wall
Wood Block
Between Studs
IMPORTANT: Refrigerant
lines must not contact wall.
Vapor Line Liquid Line
Wire Tie
Inside Wall
Strap
Sleeve
Wire Tie
Wire Tie
Strap
Wood Block
Sleeve
Vapor Line Wrapped
with Armaflex
Liquid Line
Caulk
PVC Pipe Fiberglass
Insulation
Outside Wall
IMPORTANT:
Refrigerant
lines must not
contact structure.
NOTE: Similar installation practices
should be used if line set is to be
installed on exterior of outside wall.

506860-03 Issue 1827 Page 9 of 29
Figure 11. Flushing Connections
Note: The inverted R22 cylinder must contain
at least the same amount of refrigerant as was
recovered from the existing system.
Flushing Existing Line Set and Indoor Coil
This procedure should not be performed on systems that
contain contaminants, such as compressor burn out.
Required Equipment
The following equipment is needed to ush the existing line
set and indoor coil (see Figure 11): two clean R-22 recovery
bottles, an oil-less recovery machine with a “pump down”
feature, and two sets of gauges (one for use with R-22 and
one for use with R-410A).
Flushing Procedure
IMPORTANT: The line set and/or indoor coil must be
ushed with at least the same amount of refrigerant that
previously charged the system. Check the charge in the
ushing cylinder before ushing the unit.
1. Remove existing R-22 refrigerant using the appropriate
procedure.
If the existing outdoor unit is not equipped with shutoff
valves, or if the unit is not operational AND the existing
R-22 refrigerant will be used to ush the system:
Disconnect all power to the existing outdoor unit. Connect
the existing unit, a clean recovery cylinder, and the
recovery machine according to the instructions provided
with the recovery machine. Remove all R-22 refrigerant
from the existing system. Refer to the gauges after
shutdown to conrm that the entire system is completely
void of refrigerant. Disconnect the liquid and suction lines
from the existing outdoor unit.
If the existing outdoor unit is equipped with manual shutoff
valves AND new R-22 refrigerant will be used to ush the
system:
Start the existing R-22 refrigerant system in cooling mode
and close the liquid line valve. Pump all the existing R-22
refrigerant back into the outdoor unit.
(It may be necessary to bypass the low pressure switches
to ensure complete refrigerant evacuation.)
When the low side system pressures reach 0 psig, close
the suction line valve. Disconnect all power to the existing
outdoor unit. Refer to the gauges after shutdown to conrm
that the valves are not allowing refrigerant to ow back
into the low side of the system. Disconnect the liquid and
suction lines from the existing outdoor unit.
2. Remove the existing outdoor unit. Set the new R-410A
unit and follow the brazing connection procedure
outlined previously to make line set connections. Do
not install the R-410A thermal expansion valve at
this time.
3. Make low voltage and line voltage connections to the
new outdoor unit. Do not turn on power to the unit or
open the outdoor unit service valves at this time.
4. Remove the existing R-22 refrigerant ow control
orice or thermal expansion valve before continuing
with ushing procedures. R-22 ow control devices
are not approved for use with R-410A refrigerant and
may prevent proper ushing. Use a eld-provided
tting to reconnect the lines.

506860-03Issue 1827Page 10 of 29
5. Remove the pressure tap valve cores from the unit’s
service valves. Connect an R-22 cylinder with clean
refrigerant to the suction service valve. Connect the
R-22 gauge set to the liquid line valve and connect a
recovery machine with an empty recovery tank to the
gauge set.
6. Set the recovery machine for liquid recovery and start
the recovery machine. Open the gauge set valves to
allow the recovery machine to pull a vacuum on the
existing system line set and indoor coil.
7. Invert the cylinder of clean R-22 and open its valve to
allow liquid refrigerant to ow in to the system through
the suction line valve. Allow the refrigerant to pass from
the cylinder and through the line set and the indoor coil
before it enters the recovery machine.
8. After all of the liquid refrigerant has been recovered,
switch the recovery machine to vapor recovery so that
all of the R-22 vapor is recovered. Allow the recovery
machine to pull a vacuum on the system.
NOTE: A single system ush should remove all of
the mineral oil from the existing refrigerant lines and
indoor coil. A second ushing may be done (using
clean refrigerant) if insufcient amounts of mineral
oil were removed during the rst ush. After each
system ush, allow the recovery machine to pull a
vacuum on the system at the end of the procedure.
9. Close the valve on the inverted R-22 cylinder and the
gauge set valves. Pump the remaining refrigerant out
of the recovery machine and turn the machine off.
10. Use nitrogen to break the vacuum on the refrigerant
lines and indoor coil before removing the recovery
machine, gauges, and R-22 refrigerant drum. Re-
install pressure tap valve cores into the unit’s service
valves.
11. Install the xed orice (or thermal expansion valve
approved for use with R-410A refrigerant) in the liquid
line at the indoor coil.
Refrigerant Metering Device
This unit is designed for use with TXV systems. Refer to the
appropriate following section for information on installing
the chosen refrigerant metering device.
NOTE: An R410A system will not operate properly with an
R-22 metering device.
Figure 12. Metering Device Installation
If necessary, remove R22 ow control device (xed orice/thermal
expansion valve) from existing line set before installing R410A-
approved orice or expansion valve.
Install the refrigerant metering device as shown in Figure
12. Do not twist cap tubes when loosening the seal nut from
the orice housing. Use wrench to back up the distributor.
Expansion Valve Systems
Expansion valves equipped with Chatleff-type ttings are
available from the manufacturer. See Table 3 for proper
TXV for each unit.
Table 3. TXV Data
Model Part Number
4SHP16LS-24 H4TXV01
4SHP16LS-36, -48 H4TXV02
4SHP16LS-60 H4TXV03
To install an expansion valve (see Figure 12):
1. Separate the distributor assembly and remove the
piston orice and used Teon seal. Insert nozzle end
of the expansion valve along with a new Teon seal
into the distributor and tighten to 20 - 30 ft. lbs. Use
backup wrench on all wrench ats. Overtightening will
crush the Teon seal and may cause a leak.
2. Attach liquid line portion of distributor assembly along
with new Teon seal to the inlet of the expansion valve.
Tighten to 20 - 30 ft. lbs. Use backup wrench on all
wrench ats. Overtightening will crush the Teon seal
and may cause a leak.
3. Connect the external equalizer line to the equalizer
port on the suction line and tighten to 8 ft. lbs.
4. Strap the superheat sensing bulb to the suction header.
If installing an expansion valve on an indoor coil that
previously used a xed orice, be sure to remove the
existing xed orice. Failure to remove a xed orice when
installing an expansion valve to the indoor coil will result in
improper operation and damage to the system.

506860-03 Issue 1827 Page 11 of 29
Manifold Gauge Set
Manifold gauge sets used with systems charged with
R410A refrigerant must be capable of handling the higher
system operating pressures. The gauges should be rated
for use with pressures 1 - 800 on the high side and a low
side of 30” vacuum to 250 psi with dampened speed to 500
psi. Gauge hoses must be rated for use at up to 800 psi of
pressure with a 4000 psi burst rating.
Liquid and Suction Line Service Valves
The liquid line and suction line service valves (see Figure
13) and service ports are used for leak treating, evacuation,
charging, and checking charge.
Each valve is equipped with a service port which has a
factory-installed Schrader valve. A service port cap protects
the Schrader valve from contamination and serves as the
primary leak seal.
To Access the Schrader Port:
1. Remove the service port cap with an adjustable
wrench.
2. Connect gauge to the service port.
3. When testing is completed, replace service port cap.
Tighten nger tight, then an additional 1/6 turn.
To Open Liquid or Suction Line Service Valve:
1. Remove stem cap with an adjustable wrench.
2. Use service wrench with a hex-head extension to back
the stem out counterclockwise as far as it will go. Use a
3/16” hex head extension for liquid line service valves
and a 5/16” extension for suction line service valves.
3. Replace the stem cap. Tighten nger tight, then tighten
an additional 1/6 turn.
To Close Liquid or Suction Line Service Valve:
1. Remove the stem cap with an adjustable wrench.
2. Use a service wrench with a hex-head extension to
turn the stem clockwise to seat the valve. Tighten
rmly.
3. Replace the stem cap. Tighten nger tight, then tighten
an additional 1/6 turn.
Figure 13.

506860-03Issue 1827Page 12 of 29
Suction Line (Ball Type) Service Valve
Suction line (ball type) service valves function the same
way as the other valves; the difference is in the construction
(see Figure 14).
The ball valve is equipped with a service port with a factory-
installed Schrader valve. A service port cap protects the
Schrader valve from contamination and serves as the
primary seal.
Figure 14.
Leak Testing
After the line set has been connected to the indoor and
outdoor units, the line set connections and indoor unit must
be checked for leaks.
Refrigerant can be harmful if inhaled. Refrigerant must
always be used and recovered responsibly. Incorrect or
irresponsible use of refrigerant can result in personal
injury or death.
WARNING
Never use oxygen to pressurize refrigeration or air
conditioning systems. Oxygen will explode on contact
with oil and could cause personal injury or death.
WARNING
Using an Electronic Leak Detector
1. Connect the high pressure hose of the manifold gauge
set to the suction valve service port. (Normally the
high pressure hose is connected to the liquid line port;
however, connecting it to the suction ports helps to
protect the manifold gauge set from damage caused
by high pressure.)
2. With both manifold valves closed, connect the cylinder
of R410A refrigerant. Open the valve on the R410A
cylinder (vapor only).
3. Open the high pressure side of the manifold to allow
R410A into the line set and indoor unit. Weigh in a
trace amount of R410A (a trace amount is a maximum
of 2 oz. of refrigerant or 3 lbs. pressure). Close the
valve on the R410A cylinder and the valve on the high
pressure side of the manifold gauge set. Disconnect
the R410A cylinder.
4. Connect a cylinder of nitrogen with a pressure
regulating valve to the center port of the manifold
gauge set. When using high pressure gas, such as
nitrogen, for this purpose, be sure to use a regulator
that can control the pressure down to 1 or 2 psig.
5. Adjust nitrogen pressure to 150 psig. Open the valve
on the high side of the manifold gauge set to pressurize
the line set and the indoor coil.
6. After a short period of time, open a refrigerant port to
make sure that an adequate amount of refrigerant has
been added for detection (refrigerant requirements
will vary with length). Check all joints for leaks. Purge
nitrogen and R410A mixture. Correct any leaks and
recheck.

506860-03 Issue 1827 Page 13 of 29
Evacuation
Evacuating the system of non-condensables is critical for
proper operation of the unit. Non-condensables are dened
as any gas that will not condense under temperatures and
pressures present during operation of an air conditioning
system. Non-condensables and water vapor combine with
refrigerant to produce substances that corrode copper
piping and compressor parts.
Do Not use a compressor to evacuate a system. Avoid
deep vacuum operation. Extremely low vacuums can
cause internal arcing and compressor failure. Danger of
equipment damage. Damage caused by deep vacuum
operation will void warranty.
WARNING
Use a thermocouple or thermistor electronic vacuum
gauge that is calibrated in microns. Use an instrument that
reads down to 50 microns.
1. Connect the manifold gauge set to the service valve
ports as follows:
• Low pressure gauge to suction line service valve
• High pressure gauge to liquid line service valve
2. Connect micron gauge.
3. Connect the vacuum pump (with vacuum gauge) to
the center port of the manifold gauge set.
4. Open both manifold valves and start vacuum pump.
5. Evacuate the line set and indoor unit to a minimum
of 500 microns or lower. During the early stages of
evacuation, it is desirable to close the manifold gauge
valve at least once to determine if there is a rapid
rise in pressure. A rapid rise in pressure indicates a
relatively large leak. If this occurs, the leak testing
procedure must be repeated.
6. When 500 microns or lower is maintained, close the
manifold gauge valves, turn off the vacuum pump, and
disconnect the manifold gauge center port hose from
the vacuum pump. Attach the manifold gauge center
port hose to a nitrogen cylinder with pressure regulator
set to 150 psig and purge the hose. Open the manifold
gauge valves to break the vacuum in the line set and
indoor unit. Close the manifold gauge valves.
7. Shut off the nitrogen cylinder and remove the manifold
gauge hose from the cylinder. Open the manifold
gauge valves to release the nitrogen from the line set
and indoor unit.
8. Reconnect the manifold gauge to the vacuum pump,
turn the pump on, and continue to evacuate the line
set and indoor unit until 500 microns is maintained
within a 20 minute period after shutting off the vacuum
pump and closing the manifold gauge valves.
9. When the requirements above have been met,
disconnect the manifold hose from the vacuum pump.
Open the service valves to break the vacuum in the
line set and indoor unit.

506860-03Issue 1827Page 14 of 29
Start-Up
If unit is equipped with a crankcase heater, it should
be energized 24 hours before unit start-up to prevent
compressor damage as a result of slugging.
CAUTION
1. Rotate fan to check for frozen bearings or binding.
2. Inspect all factory and eld-installed wiring for loose
connections.
3. After evacuation is complete, open liquid line and
suction line service valves to release refrigerant
charge (contained in outdoor unit) into system.
4. Replace the stem caps and secure nger tight, then
tighten an additional 1/6 of a turn.
5. Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit
nameplate. If not, do not start equipment until the
power company has been consulted and the voltage
condition corrected.
6. Set thermostat for cooling demand, turn on power to
indoor blower, and close the outdoor unit disconnect
switch to start the unit.
7. Recheck unit voltage with unit running. Power must be
within range shown on unit nameplate.
Refrigerant Charging
This system is charged with R-410A refrigerant, which
operates at much higher pressures than R-22. The liquid
line drier provided with the unit is approved for use with
R-410A. Do not replace it with one designed for use with
R-22. This unit is NOT approved for use with coils that
use capillary tubes as a refrigerant metering device.
R410A refrigerant cylinders are rose-colored.
Refrigerant should be added through the suction valve
in the liquid state.
Certain R-410A cylinders are identied as being
equipped with a dip tube. These allow liquid refrigerant
to be drawn from the bottom of the cylinder without
inverting the cylinder. Do not turn this type of cylinder
upside down to draw refrigerant.
Units are factory charged with the amount of R410A
refrigerant indicated on the unit rating plate. This charge is
based on a matching indoor coil and outdoor coil with 15’
line set. For varying lengths of line set, refer to Table 4 for
refrigerant charge adjustment. A blank space is provided
on the unit rating plate to list the actual eld charge.
Table 4. Refrigerant Charge Adjustment
Liquid Line Set Diameter Oz. Per 5 ft. adjust from 15
ft. line set*
3/8 in. 3 oz. Per 5 ft.
* If line length is greater than 15 ft., add this amount. If line
length is less than 15 ft., remove this amount.
Mineral oils are not compatible with R-410A. If oil must
be added, it must be a polyolester oil.
IMPORTANT
If the system is void of refrigerant, clean the system using
the procedure described below.
1. Use dry nitrogen to pressurize the system and check
for leaks. Repair leaks, if possible.
2. Evacuate the system to remove as much of the
moisture as possible.
3. Use dry nitrogen to break the vacuum.
4. Evacuate the system again.
5. Weigh the appropriate amount of R-410A refrigerant
(listed on unit nameplate) into the system.
6. Monitor the system to determine the amount of
moisture remaining in the oil. Use a test kit to verify
that the moisture content is within the kit’s dry color
range. It may be necessary to replace the lter drier
several times to achieve the required dryness level.
If system dryness is not veried, the compressor
will fail in the future.
The outdoor unit should be charged during warm weather.
However, applications arise in which charging must
occur in the colder months. The method of charging is
determined by the unit’s refrigerant metering device and
the outdoor ambient temperature.
Measure the liquid line temperature and the outdoor
ambient temperature as outlined below:
1. Connect the manifold gauge set to the service valve
ports as follows (see Figure 15):
• Low pressure gauge to suction line service valve
• High pressure gauge to liquid line service valve
2. Close manifold gauge set valves. Connect the center
manifold hose to an upright cylinder of R-410A.
3. If room temperature is below 70°F, set the room
thermostat to call for heat. This will create the
necessary load for properly charging the system in the
cooling cycle.

506860-03 Issue 1827 Page 15 of 29
Figure 15.
4. Use a digital thermometer to record the outdoor
ambient temperature.
5. When the heating demand has been satised, switch
the thermostat to cooling mode with a set point of
68°F. When pressures have stabilized, use a digital
thermometer to record the liquid and suction line
temperatures.
6. The outdoor temperature will determine which
charging method to use. Proceed with the appropriate
charging method.
Charge Using Weigh-In Method (Fixed Orice/TXV
Systems) - Outdoor Temperatures Below 65°F
If the system is void of refrigerant, or if the outdoor ambient
temperature is cool, use the weigh-in method to charge the
unit. Do this after any leaks have been repaired.
1. Recover the refrigerant from the unit.
2. Conduct a leak check, then evacuate as previously
outlined.
3. Weigh in the charge according to the total amount
shown on the unit nameplate.
If weighing facilities are not available or if unit is being
charged during warm weather, use one of the following
procedures.
Charge Using Subcooling Method (Fixed Orice/TXV
Systems) - Outdoor Temperatures 65°F or Above
If charging a xed orice or TXV system when the outdoor
ambient temperature is 65°F or above, the subcooling
method can be used to charge the unit.
1. With the manifold gauge hose still on the liquid
service port and the unit operating stably, use a digital
thermometer to check the liquid line temperature.
For best results, use the same digital thermometer
to check both the outdoor ambient and the liquid line
temperatures.
2. At the same time, record the liquid line pressure
reading.
3. Use the temperature/pressure chart to determine the
saturation temperature for the liquid line pressure
reading.
4. Subtract the liquid line temperature from the saturation
temperature (according to the chart) to determine
subcooling.
_________° Saturation Temperature °F
- _________° Liquid Line Temperature °F
= _________° Subcooling Value °F
5. Compare the subcooling value with those shown on
the charge label, on the back of the control cover.
If subcooling is greater than shown, recover some
refrigerant. If subcooling is less than shown, add some
refrigerant.

506860-03Issue 1827Page 16 of 29
Operation
The outdoor unit and the indoor blower cycle on demand
from the room thermostat. When the thermostat blower
switch is moved to the ON position, the indoor blower
operates continuously.
Filter Drier
The unit is equipped with a large capacity bi-ow lter
that keeps the system clean and dry. If replacement is
necessary, replace with one of similar design and capacity.
The replacement lter drier must be suitable for use with
R410A refrigerant.
Crankcase Heater
If unit is equipped with a crankcase heater, it should
be energized 24 hours before unit start-up to prevent
compressor damage as a result of slugging.
Emergency Heat Function (Room Thermostat)
An emergency heat function is designed into some room
thermostats. This feature is applicable when isolation of
outdoor unit is required or when auxiliary electric heat is
stage by outdoor thermostats. When the room thermostat
is placed in the emergency heat position, the outdoor unit
control circuit is isolated from power and the eld-supplied
relays bypass the outdoor thermostats. An amber indicating
light simultaneously comes on to remind the homeowner
that the unit is operating in the emergency heat mode.
Emergency heat is usually used during an outdoor
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. System should be left
in the emergency heat mode at least 6 hours to allow the
crankcase heater sufcient time to prevent compressor
slugging.
Heat Pump Control-Defrost Operation
The defrost termination pins must be set on the heat pump
control prior to starting the system to ensure proper defrost
operation.
The heat pump control measures differential temperatures
to detect when the system is performing poorly because
of frost buildup on the outdoor coil. The heat pump control
self-calibrates when the defrost system starts and after
each system defrost cycle. The heat pump control monitors
ambient temperature, outdoor coil temperature, and total
run time to determine when a defrost cycle is required. The
coil temperature sensor is designed with a spring clip to
allow mounting to the outside coil tubing. The location of
the coil sensor is important for proper defrost operation.
NOTE: The heat pump control 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 heat pump control initiates
defrost cycles.
Defrost Operating Modes
The heat pump control operational modes are:
• Defrost calibration and operation
• Defrost test
Defrost Termination Temperature (J1)
The heat pump control can be set to terminate the defrost
cycle at 50, 70, 90, or 100°F (10, 21, 32 and 38°C) (see
Figure 16). The termination jumper is factory set at 50°F
(10°C). If the termination jumper is not installed, the default
termination temperature is 90°F (32°C).
NOTE: Colder climates may require a higher defrost
termination temperature setting to maintain a clear coil.
Second Stage Lock-In (J2)
For second-stage heat pumps, if the outdoor ambient
temperature is below the selected compressor lock-in
temperature, the second-stage compressor solenoid will
be energized even without a Y2 thermostat input. If the
jumper is not connected to one of the temperature selection
pins (40, 45, 50, 55°F) (see Figure 16), the second-stage
lock-in feature will not be activated. Factory default is 40ºF.
Fan Cycling (J3)
When the jumper is “ON,” the fan will cycle (see Figure
16) for ve minutes if the outdoor ambient air temperature
is between 15ºF and 35ºF and the compressor has been
OFF for 25 to 30 minutes. This option helps reduce the
potential for ice build-up on the orice ring during OFF
cycles greater than 25 to 30 minutes.
Shift Delay (J4)
During the defrost cycle, if the jumper is in the “ON” position,
there will be a compressor start delay of 30 seconds to
reduce the shifting noise of the reversing valve.
Time Delay
The timed-off delay is 5 minutes long. The delay helps
to protect the compressor from short cycling in case the
power to the unit is interrupted or a pressure switch opens.

506860-03 Issue 1827 Page 17 of 29
Pressure Switch Circuit
The defrost control includes two pressure switch circuits.
A high pressure switch is connected to the board’s HI-
PS terminals (see Figure 16). The low pressure, or loss-
of-charge pressure, switch is connected to the LO-PS
terminals.
During a single demand cycle, the defrost control will lock
out the unit after the fth time that the circuit is interrupted
by a pressure switch wired to the control board. In addition,
the diagnostic LEDs will indicate a locked-out pressure
switch after the fth occurrence of an open pressure switch.
The unit will remain locked out until power to the board
is interrupted, then re-established, or until the error is
cleaned.
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 seconds start-up period
• For the rst 90 seconds each time the reversing valve
switches heat/cool modes
Figure 16. Defrost Control Board
Non-Communicating System
For systems with a non-communicating thermostat, the system
will operate based on the settings of the jumpers located on the
control board. All system settings must be done at the control
board.
Communicating System
For a communicating system, the Comfort Sync thermostat
must be used. The complete conguration of the outdoor unit
is performed using the Comfort Sync thermostat. For complete
details on how to integrate this unit into a Comfort Sync-enabled
system, please refer to the Comfort Sync Wi-Fi installer’s system
setup guide.
100
90
70
50
100
90
70
50
100
90
70
50
100
90
70
50
100
90
70
50
55
50
45
40
55
50
45
40
55
50
45
40
55
50
45
40
ON
OFF
30
PSC
LO PS HI PS Y1 OUT Y2 OUT OUT
O
R I+ I - C DS O Y1 Y2 L W
COIL AMB DIS
OPEN = OFF OPEN = 90 F
2ND STAGE
LOCK IN
55 F
50 F
45 F
40 F
DEFROST
TERMINATION
100 F
90 F
70 F
50 F
COMP SHIFT
DELAY
J4J3
FAN
CYCLING
J1 J2

ECM
Y1
ECM
Y2
COM PARK FAN
PWM
DS TO R
7-Segment
Display
Push
Button
J2 (Two-Stage
Heat Pump Only)
Second Stage Lock-In
Temperature
55 Degree
Target
50 Degree
Target
45 Degree
Target
40 Degree
Target
(Default)
J4 (HP Only)
Compressor Shift Delay
30 Second
Delay
(Default)
No Delay
J1 (HP Only)
Defrost Termination Temperature
100 Degree
Target
90 Degree
Target
70 Degree
Target
50 Degree
Target
Default When
Jumper is
Removed or
Missing
90
J3 (All Units)
Fan De-Icing
Jumper ON
Fan On 5 Minutes
Jumper OFF
Digable (Default)
DS to R Jumper (Two-Stage Heat Pump Only)
Break off DS to R jumper if Enhanced Dehumidication Accessory (EDA) is used
with Comfort Sync thermostat (two-stage units only).

506860-03Issue 1827Page 18 of 29
Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover
E105 Device communication problem - No other devices on RS
BUS (Communication system).
Equipment is unable to communicate. Indicates numerous
message errors. In most cases, errors are related to electrical
noise. Make sure high voltage power is separated from
RSBus. Check for mis-wired and/or loose connections
between the stat, indoor unit, and outdoor unit. Check for a
high voltage source of noise close to the system. Fault clears
after communication is restored.
E120 Unresponsive device (Communicating systems only). Usually caused by delay in outdoor unit responding to indoor
unit poling. Recycle power. Check all wiring connections.
Cleared after unresponsive device responds to any inquiry.
E124 Active communicating thermostat signal missing for more
than 3 minutes (Communicating systems only).
Equipment lost communication with the thermostat. Check
four wiring connections, ohm wires, and cycle power at the
thermostat. Alert stops all services and waits for heartbeat
message from thermostat (subnet controller). Cleared after
valid thermostat (subnet) message is received.
E125 Control failed self-check, internal error, failed hardware.
Will restart if error recovers, Integrated control not
communicating Covers hardware errors (ame sense
circuit faults, pin shorts, etc).
Hardware problem on the control. Cycle power on control.
Replace if problem prevents service and is persistent. Cleared
300 seconds after fault recovered.
E126 Control internal communication problem. Hardware problem on the control. Cycle power on control.
Replace if problem prevents service and is persistent. Cleared
300 seconds after fault recovered.
E131 Corrupted control parameters (Verify conguration of
system) (Communicating systems only).
Recongure the system. Replace control if heating or cooling
is not available. Only applicable in the communicating mode
not in startup. Exit from Commissioning and Execute Se+
factory Default mode. Control will still operate on default
parameter settings.
NOTE: Additional codes may be found in the Comfort Sync room thermostat manual.
Table 5. 7-Segment Alert and System Status Codes
7-Segment Alert and System Status Codes
Alert codes are displayed using the 7-segment display
located on the outdoor control.
NOTE: System fault and lockout 7-segment display alarm
codes take precedence over system status codes (cooling,
heating stages or defrost/dehumidication). Only the latest
active fault or lockout alarm code, if present, will be displayed.
If no fault or lockout codes are active, then system status
codes are routinely displayed.
The 7-segment will display an abnormal condition (error
code) when detected in the system. A list of the codes are
shown in Table 5.
Resetting Alert Codes
Alert codes can be reset manually or automatically:
Manual Reset
Manual reset can be achieved by one of the following
methods:
• Disconnecting R wire from the main control’s R terminal.
• Turning the indoor unit off and back ON again. After
power up, all existing codes will display for 60 seconds
and then clear.
Automatic Reset
After an alert is detected, the main control continues to
monitor the unit’s system and compressor operations.
When/if conditions return to normal, the alert code is turned
off automatically.

506860-03 Issue 1827 Page 19 of 29
Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover
E180 Outdoor air temperature sensor failure. Only shown if
shorted or out of range (Communicating systems only)
Compare outdoor sensor resistance to temperature
resistance charts in unit installation instructions. Replace
sensor pack if necessary. At beginning of (any) conguration,
furnace or air handler control will sense outdoor air and
discharge air temperature sensor(s) If detected (reading
in range), appropriate feature will be set as installed and
that could be seen in 'About ' screen. In normal operation
after control recognizes sensors, alarm will be sent if valid
temperature reading is lost. To get rid of setting and alarm,
redo conguration and make sure that temperature sensor is
marked as not installed in indoor Unit ‘About’ screen. When
indoor unit control is replaced thermostat will ‘tell’ new control
if temperature sensor is in system or not. Clears 30 seconds
after fault recovered.
E409 LSOM - Compressor low voltage. Secondary voltages below 18VAC. After 10 minutes, operation
is discontinued. Clears the code after voltage is higher than
20VAC for 2 seconds or after power reset.
E410 The outdoor unit pressure is below the required limit. Unit pressure is below the lower limit. The system is shut
down. The low pressure switch for HFC410A will open at
40 PSIG and close at 90 PSIG. Conrm that the system is
properly charged with refrigerant. Check TXV, indoor unit
blower motor, dirty lters or clogged refrigerant lter. Conrm
that the evaporator coil is clean. The alarm clears after the
pressure switch closes or after a power rest.
E411 The low pressure switch has opened 5 times during one
cooling cycle. As a result, the system will shut down.
Open low pressure switch error count reached 5 strikes. The
low pressure switch for R410A will open at 40 PSIG and close
at 90 PSIG. Conrm that the system is properly charged with
refrigerant. Check TXV, indoor unit blower motor, dirty lters
or clogged refrigerant lter. Conrm that the evaporator coil is
clean. The alarm clears after a power rest.
E412 The outdoor unit pressure is above the required limit. The
system will shut down.
Unit pressure is above the upper limit. System is shut down.
The high pressure switch for HFC410A will open at 590 PSIG
and close at 418 PSIG. Conrm that the system is properly
charged with refrigerant. Check condenser fan motor, TXV,
indoor unit blower motor, stuck reversing valve or clogged
refrigerant lter. Conrm that the outdoor unit is clean. The
alarm clears after 4 consecutive normal compressor run
cycles, the pressure switch closes or a power reset.
E413 The high pressure switch has opened 5 times during one
cooling cycle. As a result, the Comfort Sync thermostat
will shut down.
Open high pressure switch error count reached 5 strikes.
System is shut down. The high pressure switch for HFC410A
will open at 590 PSIG and close at 418 PSIG. Conrm that the
system is properly charged with refrigerant. Check condenser
fan motor, TXV, indoor unit blower motor, stuck reversing
valve or clogged refrigerant lter. Conrm that the outdoor unit
is clean. The alarm clears after a power reset.
E414 The discharge line temperature is higher than the
recommended upper limit of 279°F.
Discharge line temperature is > 279°F. Conrm that the
system is properly charged with refrigerant. Check system
operating pressures and compare to unit charging charts in
installation manual. Conrm that the outdoor unit is clean. The
alarm clears after the discharge temperature is < 225°F.
E415 The discharge line temperature has been consistently
higher than the recommended upper limit of 279°F.
Discharge line high temperature error count reached 5
strikes. Conrm that the system is properly charged with
refrigerant. Check system operating pressures and compare
to unit charging charts in installation manual. Conrm that the
outdoor unit is clean. The alarm clears after the discharge
temperature is < 225°F. The alarm clears after a power reset.
NOTE: Additional codes may be found in the Comfort Sync room thermostat manual.
Table 5. 7-Segment Alert and System Status Codes

506860-03Issue 1827Page 20 of 29
Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover
E416 The outdoor coil sensor is either open, short-circuited
or the temperature is out of sensor range. As a result,
the outdoor unit control will not perform any defrost
tempering.
Coil sensor being detected open or shorted, or temperature is
out of coil sensor range. Outdoor unit control will not perform
demand or time/temperature defrost operation. System will
still heat or cool. Check the resistance of the coil sensor and
compare to temperature resistance chart. Replace coil sensor
if needed. The alarm clears when outdoor unit control detects
proper coil sensor readings or after a power reset.
E417 The outdoor unit discharge sensor is either open, short-
circuited or the temperature is out of sensor range. As a
result, the outdoor unit control will not perform any defrost
tempering.
Outdoor unit control detects open or shorted discharge
sensor, or temperature that is out of discharge sensor range.
Check the resistance of the discharge sensor and compare
to temperature resistance chart; replace if needed. Reset
by replacing the discharge sensor. This fault is detected
by allowing the unit to run for 90 seconds before checking
discharge sensor resistance. If the discharge sensor
resistance is not within range after 90 seconds, the board will
count one fault. After 5 faults, the board will lock out. Check
for proper sensor reading and attachment to line. The alarm
clears after a power reset.
E418 There is a faulty W output circuit. Faulty W output circuit. Conrm that the unit is not running.
Check for mis-wiring. Disconnect thermostat lines from W
and verify 24VAC on the W. If 24VAC is present, replace the
board.
E419 The W output on the outdoor unit has reported more
than 5 errors. As a result, the system has shut down the
outdoor unit.
W output hardware fault count reached 5 strikes.
E420 The heat pump defrost cycle has taken more than 20
minutes to complete.
Defrost cycle lasts longer than 20 minutes. This alarm is
applicable with non-communicating heat pump system only.
Check heat pump defrost operation. The alarm is cleared after
the “W1” signal is removed.
E421 The W output terminal on the outdoor unit is not wired
correctly.
Voltage sensed on W and O when Y1 thermostat input is
deactivated. Another device or wiring fault is energizing W
check wiring. The alarm clears when wiring is corrected or
after a power reset.
NOTE: Additional codes may be found in the Comfort Sync room thermostat manual.
Table 5. 7-Segment Alert and System Status Codes