The air conditioning
condenser could be fouled enough to reduce heat transfer and trip the high pressure alarm
, but not fouled enough to restrict flow.
If so, disconnect the raw water
supply from the pump
and fill the condenser with a 50/50 mixture of Rydlyme or CLR and water
by pouring the mixture into the hose with a funnel. Make sure that the hose level is correct to let the condenser fill with solution. Let it set for an hour and then flush.