40DC AC Problems

[cnairn]

Have been having problems with LPF error in salon AC for several months. Have had it looked at 3 times with attempted fixes most along lines of coolant leak or wrong coolant in system. Still getting error. Got to boat in Northern Alabama last night to find the other AC to the front and rear staterooms will not stay on - tripping breaker everytime after about 3-5 seconds. Therefore no working AC at all. Not much professional help here at Goose Pond. Any ideas??? We are HOT!!!

[Pete]

I would suggest ruling out a power problem first. Disconnect shore power and start up the onboard generator. Check the electric panel volt and amp meters, verifying the proper voltage (either 120 or 240, I am not sure which is used on the 40DC), and that the amp meter is close if not at zero. While watching these meters, have someone start the stateroom AC and observe what the meters do and if the AC reacts different than when on shore power. Post back the results.

[Boatsb]

LPF is low pressure fault. Either your low on refrigerant or a bad sensor woukd cause that.

Breakers blowing could be capacitors.

[Pascal]

First thing to check for low pressure error are pressures if too low then someone needs to use a sniffer to find the leak.

For the Tripping breaker, as Pete said check voltage and amp meters first. If amp do not spike high when compressor tries to start it could be the breaker

If amps spike over say 15/20 amp it could be anything from a bad compressor, start capacitor or a short in the wiring

Does the compressors for a second or two before tripping or does it not start at all?

[DavidSmith]

I think LPF can also indicate that their is not enough seawater flow through the system. Have you checked your strainer? Are there barnacles growing in your intake?

David Smith
Hatteras 36

[Pascal]

No. low pressure is just that. Lack of sea water flow triggers a high pressure shut down, not low

[cnairn]

Thanks everyone for the help. Diesel mechanic 2 slips over helped. We added refrigerant and salon is working. I still fear a leak needs to be found as the longer term solution. The compressor appears the problem for the other unit and he is having one built as apparently Marine air unit I have is no longer available.

[Reefgeorge]

You can find a leak with a detector or carefully check all of the connections and joints with your bare fingertips, looking for refrigerant oil. It leaks out with the refrigerant. A leak in the heat exchanger or buried copper lines are tougher to find because they are hidden. If it leaks faster at rest then it is most likely the low side because the suction side sits at twice the operating pressure when at rest. The opposite is true if it leaks more when running.

George