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My 1986 33 FBC has the standard 16K BTU cruise-air with the SMX II digital controls. The pump and compressor are the same ones that were on the boat when I bought it back in 2002 (maybe they´re original?). I had the SMX II controls installed back in 2003. So far they´ve worked fine.

I splashed the boat on Sunday night but the power is not turned on at my marina yet. I had a number of things to work on tonight so I fired up the generator and got the heat going (its only in the low 40´s tonight). After 2-3 hours I got ready to leave the boat and hit the off switch on the SMX II panel and while the fan stopped blowing, I could hear the pump and compressor still running. They wouldn´t stop until I switched off the unit´s breaker at the panel. As soon as you flip the breaker back on the unit starts right up again and will not shut off by hitting the SMX II´s OFF button. The pump and compressor will only shut down when the breaker is switched off. While its running I can switch between Cool and Heat with no issues. The fan speeds up and slows down as temp is changed, but the unit will not shut down.

Any ideas?

A CX bath on the back of the controls, especially the circuit boards. Sounds like the relay that controls the compressor and pump is sticking, but probably not the relay but the signal from the control panel is "stuck" in the "run" position.

Bruce, what ya think?

UV

Thanks UV. That's funny, I was thinking last night that it was high time I had my own CX miracle cure story.

First pull the modular plugs at the back of the control and down at the power box and check for green corrosion on the contacts both plug and socket. It looks like a modular network end.

If everything looks okay do a factory reset to see if that changes anything.

To restore all programming functions to the Factory Setting,

first switch to Off Mode and then simultaneously press and

hold the POWER and MODE keys.

Hold keys for three seconds while “00” flashes in the display.

Successful memory reset is indicated by a “1” flashing back and forth
across the display; release keys.

System returns to the Off
Mode.

After that your looking at either the power board down at the unit or the display itself.

Thanks Bruce. So no CX?

You could spray the plug ends with CX if you'd like after checking, but I would go thru the reset before I'd start spraying randomly.

After that if you think its a moisture problem then have at it.

Thanks Bruce. Other than keeping the raw water strainer clean and the vents clean, is there any other preventative/normal maintenance that needs to be done on the compressor or pump?

The water cooled condensing coil needs to be cleaned out every 3 to 5 years depending on water content.

The coating that builds up prevents the heat transfer between the high pressure freon and the cooling water leading to higher than normal head pressures and temps which makes the unit worker harder and less efficient.

Some pump motors have oil holes for the bearings. 3 in 1 oil works good for that.

Unplugging and reconnecting and factory reset did not work so I called Cruisair. They suggested the problem was the triac on the power box. Fortunately one of the members at my club does a lot of repair work on Cruisair and he had a triac in his truck ($35). I changed it yesterday and the AC worked perfectly.

Thanks for all the suggestions.

Triac shorts are common as the heat sinks are minimal at best.

Good heat conducting paste under the body helps.

The part came with a small packet of white grease. I used it liberally.