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Repair Procedures
WARNING: WHEN SERVICING THE OUTDOOR UNIT, BE SURE TO TURN OFF POWER TO THE INDOOR UNIT.
The outdoor disconnect switch will not cut low voltage power, and damage to the control board will occur if
the main heat pump breaker is not turned off during service.
Pumpdown Procedure
1. Place the unit in SERVICE mode via the PC App or LCD interface; this will open the EEVs and start the indoor circu-
lator (as long that circulator is powered and controlled by the heat pump). DO NOT turn off electrical power at the
breaker panel, since the coaxial coil must have full water flow during refrigerant recovery. Be sure to TURN OFF
POWER to indoor unit after pumpdown is completed, as per above warning.
2. Connect the refrigerant recovery unit to the heat pump's internal service ports via a refrigeration charging manifold
and to a recovery tank as per the instructions in the recovery unit manual. Plan to dispose of refrigerant if there was
a compressor burnout.
3. All refrigerant to water heat exchangers (coaxial coils, brazed plates) must either have full flow or be completely
drained of fluid before recovery begins. Failure to do so can freeze and rupture the heat exchanger, voiding
its warranty. (Note that this does not apply to desuperheater coils.)
4. Ensure all hose connections are properly purged of air. Start the refrigerant recovery as per the instructions in the
recovery unit manual.
5. Allow the recovery unit suction pressure to reach a vacuum. Once achieved, close the charging manifold valves.
Shut down, purge and disconnect the recovery unit as per the instructions in its manual. Ensure the recovery tank
valve is closed before disconnecting the hose to it.
6. Connect a nitrogen tank to the charging manifold and add nitrogen to the heat pump until a positive gauge pressure
of 5-10 psig is reached. This prevents air from being sucked into the unit by the vacuum when the hoses are discon-
nected.
Turn off power to heat pump. The heat pump is now ready for repairs.
General Repair Procedure
1. Perform repairs to system.
Always ensure nitrogen is flowing through the system at the lowest flow rate that can be felt at the discharge dur-
ing any brazing procedures to prevent soot buildup inside the pipes.
It is recommended to replace the liquid line filter-dryer any time the refrigeration system has been exposed to the
atmosphere.
Place a wet rag around any valves being installed, as almost all valve types have non-metallic seats or seals
that will be damaged by excessive heat, and aim the torch flame away from the valve body. Solder only one
joint at a time and cool joints down in between.
2. Pressure test the system with nitrogen. It is recommended to check for leaks using leak detection spray, Spray
Nine, or soapy water. Check at 10, 25, 50 and 100 psig. Allow the system to sit at 100 psig for at least an hour,
then re-check.
Vacuuming & Charging Procedure
After completion of repairs and nitrogen pressure testing, the refrigeration circuit is ready for vacuuming.
1. Release the nitrogen pressure and connect the vacuum pump to the charging manifold. Start the vacuum pump and
open the charging manifold valves. Vacuum until the vacuum gauge remains at less than 500 microns for at least 1
minute with the vacuum pump valve closed.
2. Close the charging manifold valves then shut off and disconnect the vacuum pump. Place a refrigerant tank with the
proper refrigerant on a scale and connect it to the charging manifold. Purge the hose to the tank.
3. Weigh in the appropriate amount and type of refrigerant through the low pressure (suction) service port. Refer to the
nameplate label on the unit for the proper refrigerant type and charge amount.
4. If the unit will not accept the entire charge, the remainder can be added through the low pressure service port after
the unit has been restarted.
ISSUE 03: 1-Oct-2021
Page 61
002291MAN-03
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