As the previous poster said, HPF is high pressure fault probably caused by low/no raw water
flow or a fouled condenser.
First check for raw water
. It should be a solid stream. If not check the water
pump">raw water pump, they do fail. Also make sure that it is not blocked by an air bubble. Remove the cover on the strainer to make sure good raw water flow is available and try again.
If you are getting decent flow or diminished flow then your condenser is fouled and needs to be acid cleaned. Disconnect the raw water hose from the pump to the condenser at the pump end. Raise it up and pour in a 50/50 mixture of Rydlime, CLR or Barnacle Buster. Drop the hose until you see the level rise but not overflow and leave it there for several hours. Reconnect and flush with raw water.