WARNING !!!! Dealer & Service Center Use Only
LEVEL-2 FAULT CODES
Message Error Description
Possible Cause
[dPO]
Defrost Sensor Open Cut or loose sensor wiring
[PO]
Water Temperature
Sensor Open
Cut or loose sensor wiring
[dPC]
Defrost sensor
shorted
Short circuit in defrost sensor wiring or defective sensor.
[PC]
Water temperature
sensor shorted
Short circuit in water sensor wiring or defective sensor.
[LP]
Refrigerant system
low pressure switch
open
System refrigerant charge low or defective low-pressure switch.
[HP]
Refrigerant system
high pressure switch
open
Low water flow, defective high-pressure switch or wiring.
[FLO]
Low or no water
flow detected
Circulating pump off, isolation valves set improperly, defective
water pressure switch.
[FS]
Heater in defrost
mode
Normal function in lower air temperatures. Fan continues to run
and compressor is off. Compressor will restart when air coil
temperature reaches 38
°
F or above.
[CSE]
Control system error Control may need reset. Disconnect then reconnect power to reset
control if error continues replace control board.
DEFROST CYCLE OPERATION:
The Microprocessor Control monitors the heater’s air-coil temperature, minimizing air-coil
freeze-up during cooler weather conditions. Should the control sense air-coil temperatures
conducive to making ice, the heater’s compressor operation is interrupted while the fan is
allowed to continue in operation. With the compressor off, the air coil begins to warm to the
surrounding air temperature. As air-coil temperatures rise above approximately 38
°
F, the
compressor is restarted and heating resumes. In the event air temperatures remain below
approximately 38
°
F, the compressor will remain off until the air temperature rises above
approximately 38
°
F. Heating of water will not be taking place as long as the compressor
remains off.
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