41
Fault Code Troubleshooting Guide
connector. Refer to chart #2 (p.33) for expected resistance value. If the measured resistance is >200
Ω
or =0
Ω
, the thermisitor is faulty.
•
Replace thermisitor assembly.
Control board faulty-
•
Replace control board.
•
If replacing the control board doesn’t resolve the issue, contact technical support.
Coil Temperature Sensor Short or Open or Ad Error (Coil temperature sensor circuit is
not functioning):
Loose connection or damaged wire-
•
Turn off power at the circuit breaker / fuse box.
•
Check that connector CN212 on control board is seated.
•
Check wires for damage.
Discharge temperature sensor is shorted or open-
•
Unplug ribbon cable from CN212; check resistance between pins 5 and 6 of the ribbon cable
connector, refer to chart #1 (p.33) for expected resistance value. If the measured resistance is >40
Ω
or = 0
Ω
, the thermisitor is faulty.
•
Replace thermisitor assembly.
Control board faulty-
•
Replace control board.
•
If replacing the control board doesn’t resolve the issue, contact technical support.
Low Water Level Alarm (The tank is not full of water):
Tank is not completely
fi
lled with water-
•
Ensure that the tank is completely
fi
lled and cycle power off and back on to restart dry
fi
re protection.
Fault is still present-
•
Call tech services.
Heat Pump Low Pressure Fault (Lower pressure switch is open):
Low suction pressure-
•
Use a service gage set to check system pressures (high and low sides).
•
The low side pressure switch opens if suction pressure drops below 7.3 psi. and will reset (close)
when pressure exceeds 21.8 psi; if suction pressure is less 21.8 psi, the low pressure switch is open,
preventing the compressor from running.
•
Can be caused by poor air
fl
ow across the evaporator; make sure the evaporator and air
fi
lter are free
of dust and dirt build up, see “Cleaning the Air Filter” (p.11) and “Cleaning the Evaporator” (p.35).
•
Can be caused by low refrigerant charge or a blockage in the refrigerant system.
Low side pressure checks good-
•
Disconnect the wires from the low pressure switch and check.
Heat Pump High Pressure Fault (High pressure switch is open):
High discharge pressure-
•
Use a service gage set to check system pressures (high and low sides).
•
The high pressure switch opens at 338 psi and resets when pressure drops below 275 psi.; if it is 275
psi or higher then the pressure switch is open, preventing the compressor from running.
•
Can be caused by poor air
fl
ow across the evaporator; make sure the evaporator and air
fi
lter are free
of dust and dirt build up, see “Cleaning the Air Filter” (p.11) and “Cleaning the Evaporator” (p.35).
•
Can be caused by blockage in the refrigerant system or low water level in tank.
High side pressure is less than 275 psi.-
•
Disconnect the wires from the high pressure switch and check resistance across the terminals; 0
