Hayward HP50HA Troubleshooting Manual page 25

3. Error Code: E01
An Error Code: E01 relates to a problem detected on the high refrigerant pressure side.
This could be caused by a problem with the pressure switch, pressure switch wiring,
control board PCB, the water supply, the filter dryer, or the Heat Pumps refrigerant
charge.
Does Error Clear? Power Down & Test Pressure Switch
Step 3A
Step 3B
To isolate an E01 error, first verify whether the error Power down heat pump, disconnect high pressure
clears when the heat pump is not running. IF the error switch wires & measure switch for resistance. IF
clears, go to 3D. IF the error does not clear, jump to resistance is identified, replace switch (HPX2001-3605).
step 3B. IF no resistance, go to step 3C.
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