Re: Air conditioner seawater pump won’t start

Dean Gillies

Hi Mark, Bill, Matt & Danny,

Thanks for posting. 

It turned out that the problem I was having was nothing to do with the capacitor, corrosion or the rotor sticking. The clue was in the lack of drive voltage to the pump.  My capacitor is good, there is no corrosion and the rotor turns freely.

The problem was simply that the seawater pump is not commanded to turn on until the ambient temp is below the set point.  In warm climates this usually happens immediately, but if the air temp is 15degrees as it is here, the pump is not commanded to turn on because it’s simply not required by the system.

Bill, that’s probably good info for your book as I’m sure this happens to others, but not many.  I only needed the pump to run for pushing antifreeze around the lines.  I now know how to do that, by using a heat gun on the thermostat!

Interestingly I do have the plastic capacitor, but have had no issues with it, even although the AC has been used a lot since the boat was new. The previous owner didn’t take the boat out very often, but he did like to hang out in the marina in the Italian summer with the AC running!

SY Stella

ps Danny, I don’t know that crc 66 product, but I’ll keep an eye open.  I do use CorrosionX and of course WD40 is as ubiquitous as duct tape :-)
As the old saying goes ...
If it moves when it shouldn’t -> Duct Tape
if it should move but doesn’t -> WD40

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