AC fault HPF

[Paul_S123]

I had the survey done on the Phantom, all was good except a few minor niggles.

The ac was working fine in the morning.

The boat was lifted at lunchtime (without closing the a/c seacock). Relaunched and sea trialled.

Back at the dock, the ac was running well, but then the 2 displays in the salon kept flashing HPF and cutting out. The ones in the cabins kept working fine.

The cooling pump felt very hot to touch.

The boats skipper (who is the boats manager) felt the strainer might be blocked. The broker (via the telephone) felt it was an air block sometimes caused by lifting without closing the seacock (which we did).

Thoughts?

 

[kashurst]

you get an HPF fault if there is insufficient cooling. The units in the cabins probably just hadn't done enough work yet to cause the same fault as it usually cooler down below. So either an air lock or a blockage especially if all was well before the lift out.

Air con pumps are usually below the water line as they are centrifugal solid impeller pumps. I have had after a lift, an airlock form that prevents the pump from self priming. Sometimes there is a bleed screw just above the pump to prime the cooling system - let the trapped air out and water in. Once the pump is full of water it should be fine and will push any air out of the system in a few seconds. I would ask them to confirm in writing the problem is sorted (5 min job).

Fingers crossed hope it all goes through.

 

[superheat6k]

Diagnosis sound spot on. Lack of cooling water to the condenser causes the compressor discharge or HP to rise, when it hits the safe limit the High Pressure switch cuts out causing the HPF fault, and shuts down the compressor. On some systems these have a manual reset button on the switch sensor.

Likely the reason the Channel Tunnel shuttle trains are stopping working presently - most AC systems in the UK can only work to around 30-35oC ambient, and if the condenser coils are a bit dirty they start stopping just when they are needed most.