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Table 13 — Troubleshooting
LEGEND
FAULT HEATING COOLING POSSIBLE CAUSE SOLUTION
Main Power Problems X X Green Status LED Off Check line voltage circuit breaker and disconnect.
Check for line voltage between L1 and L2 on the contactor.
Check for 24-vac between R and C on controller.
Check primary/secondary voltage on transformer.
HP Fault — Code 2
High Pressure
X Reduced or no water flow in
cooling
Check pump operation or valve operation/setting.
Check water flow adjust to proper flow rate.
X Water temperature out of range
in cooling
Bring water temperature within design parameters.
X X Overcharged with refrigerant Check superheat/subcooling vs. typical operating condition.
X X Bad HP switch Check switch continuity and operation. Replace.
LP/LOC Fault — Code 3
Low Pressure/Loss of
Charge
X X Insufficient charge Check for refrigerant leaks.
X Compressor pump down at
start-up
Check charge and start-up water flow.
FP1 Fault — Code 4
Source Water Freeze
Protection
X Reduced or no water flow in
heating
Check pump operation or water valve operation/setting.
Plugged strainer or filter. Clean or replace.
Check water flow adjust to proper flow rate.
X Inadequate antifreeze level Check antifreeze density with hydrometer.
X Improper freeze protect setting
(–1.1 C vs –12.2 C)
Clip JW3 jumper for antifreeze (–12.2 C) use.
X Water temperature out of range Bring water temperature within design parameters.
X X Bad thermistor Check temperature and impedance correlation.
FP2 Fault — Code 5
Load Coil Freeze
Protection
X Reduced or no water flow in
heating
Check pump operation or water valve operation/setting.
Plugged strainer or filter. Clean or replace.
Check water flow adjust to proper flow rate.
X Improper freeze protect setting
(–1.1 C vs –12.2 C)
Clip JW3 jumper for antifreeze (–12.2 C) use.
X Water temperature out of range Bring water temperature within design parameters.
X X Bad thermistor Check temperature and impedance correlation.
Over/Under Voltage —
Code 7
(Auto Resetting)
X X Under voltage Check power supply and 24-vac voltage before and during operation.
Check power supply wire size.
Check compressor starting.
Check 24-vac and unit transformer tap for correct power supply voltage.
X X Over voltage Check power supply voltage and 24-vac before and during operation.
Check 24-vac and unit transformer tap for correct power supply voltage.
Performance Monitor —
Code 8
X Heating mode FP2>51.7 C Check for overcharged unit.
X Cooling mode FP1>51.7 C OR
FP2< 4.4 C
Check for poor water flow or airflow.
No Fault Code Shown X X No compressor operation See scroll compressor rotation section.
X X Compressor overload Check and replace if necessary.
X X Control board Reset power and check operation.
Unit Short Cycles X X Unit in Test mode Reset power or wait 20 minutes for auto exit.
X X Unit selection Unit may be oversized for space. Check sizing for actual load of space.
X X Compressor overload Check and replace if necessary.
Unit Does Not Operate in
Cooling
X Reversing valve Set for cooling demand and check 24-vac on RV coil and at control.
If RV is stuck, run high pressure up by reducing water flow and while operat-
ing engage and disengage RV coil voltage to push valve.
X Thermostat setup Check for ‘O’ RV setup not ‘B’.
X Thermostat wiring Check O wiring at heat pump. Jumper O and R for RV coil.
Insufficient Capacity/
Not Cooling or Heating
Properly
X X Low refrigerant charge Check superheat and subcooling.
X X Restricted metering device Check superheat and subcooling. Replace.
X Defective reversing valve Perform RV touch test.
X X Thermostat improperly located Check location and for air drafts behind thermostat.
X X Unit undersized Recheck loads and sizing. Check sensible cooling load and heat pump
capacity.
X X Scaling in water heat exchanger Perform scaling check and clean if necessary.
X X Inlet water too hot or cold Check load, loop sizing, loop backfill, ground moisture.
High Head Pressure X Scaling in water heat exchanger Perform scaling check and clean if necessary.
X X Unit overcharged Check superheat and subcooling. Reweigh in charge.
X X Non-condensables in system Vacuum system and reweigh in charge.
X X Restricted metering device Check superheat and subcooling. Replace.
Low Suction Pressure X Reduced water flow in heating Check pump operation or water valve operation/setting.
Plugged strainer or filter. Clean or replace.
Check water flow adjust to proper flow rate.
X Water temperature out of range Bring water temperature within design parameters.
FP — Freeze Protection
HP — High Pressure
LED — Light-Emitting Diode
LOC — Loss of Charge
LP — Low Pressure
RV — Reversing Valve