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Troubleshooting Using Displayed Codes
Interpreting Error Codes
The HP7R heat pump microprocessor controller is designed to be self-diagnostic through the display
of various fault codes.
Owners & Operators: If you believe you are experiencing a problem with the heater, and feel a need to
call the factory for assistance, it will be beneficial to let the factory Service Representative know which
code is being displayed. Having this information at hand will permit the Service Representative to work
through–with you–any site related issues causing or contributing to the problem. Then, if after working
through site-related issues the heater is still not functioning correctly, the Service Representative will
offer to set up a service visit. As necessary, please Contact AquaCal Customer Support Group (800-
786-7751).
Dealers and Service Centers: For troubleshooting use, listed below are all possible fault messages
output by the microprocessor, what the codes mean, and possible causes with solutions for the
indicated problem. Please contact AquaCal Technical Support Group, as necessary (800-786-7751).
Controls Configuration & Adjustments...
WARNING !
Failure to heed the following may result in permanent
injury or death.
Heat pumps contain no owner or operator repairable components. Repairs must
not be
attempted by untrained and/or unqualified individuals. If service is deemed necessary, contact
installing dealer or AquaCal Customer Support at (800) 786-7751.
(HEAT-ONLY UNITS)
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 temperature sensor or defective sensor.
[LP]
Refrigerant System Low
Pressure Switch Open
System refrigerant charge low, defective low pressure switch, clogged
evaporator coil, or defective wiring.
[HP]
Refrigerant System High
Pressure Switch Open
Low water flow, defective high pressure switch, or defective wiring.
[HP5]
5 High Pressure Faults Within
One (1) Call for Heating or
Cooling (Lock Out Condition)
See causes for [HP]
[LP5]
5 Low Pressure Faults Within
One (1) Call for Heating or
Cooling (Lock Out Condition)
See causes for [LP]
[OTA]
Over Temperature Alarm<
Temperature over 110
o
F (Unit
Locked)
Defective compressor contactor, defective controller, or defective
water temperature sensor.
[FLO]
Low or No Water Flow
Detected
Circulating pump off, water filter dirty, isolation valves set improperly,
or defective 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
o
F or above.
[CSE] Control System Error
Controller may need to be reset. Disconnect then reconnect power to
controller. If error continues, replace control board, display board, or
both.
[CEr] Communication Fault
Loss of communication between main board and display board. Reset
controller or replace communication cable.