AC Compressor Will Not Shut Off

[divert00]

1986 63MY, 7 ac units. Salon AC, Cruiseair, 26000 btu, smx II control, likely 1986 original. Cools fine, has worked perfectly our 16 months of ownership. Symptoms: control panel turns off cooling, but
compressor continues to run as does raw water pump. Can only stop compressor and pump by turning off salon ac breaker. Removed yellow wire from simx control, same result. Looked in Cruiseair control
box marked “salon ac” (pictured) and circuit board and other small box have been bypassed. Box only serves as a junction box. Same result if I change to heat mode. I tapped on all components in control
box attached to compressor unit, no change. I am thinking there is a newer controlbox with a stuck
relay located elsewhere, but cannot find. I am calling ac tech tomorrow, but looking for advice.

John McCarley
Water Colors
Wrightsville Beach NC

 

[Briankinley2004]

I would have said the circuit board in the box in your picture was bad but looks like that has already been eliminated. BTW Flightsystems will rebuild that for you. Tyler McFarland was my contact there and walked me through the trouble shooting

 

[MadHatter53]

I had the same problem with my salon unit. I think ii was the triac but not 100% sure he was repairing another unit that had a bad trigger.

 

[SKYCHENEY]

Agree with bad triac. The triacs are a standard unit and you don't have to buy the Cruiseair ones that are a ripoff.




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[divert00]

I am not at the boat this week, so I cannot look. Is the triac located in the metal box that is attached to the compressor unit. (Not the box on the bulkhead, which I pictured.)

 

[finatic]

I just started having the same issue with my salon unit. Where is that Triac located?

 

[divert00]

After digging through Dometic documents on the www, I believe my ac units have been updated to use DX Pump Relay units. These allow up to 8 ac compressors to be supported by 1 raw water pump. This would explain why the original cruiseair box that I pictured, is now gutted of any control components. Of course ,these do contain a triac and I agree this is likely source of my problem. Now to find that sucker. I have ordered 2 triacs, as shown in previous post. As always, thanks for the advice.

 

[MadHatter53]

I have two boxes in my port eng room that have the triggers, triacs etc for my 4 units.

 

[divert00]

Replaced triac, problem solved.

 

[MadHatter53]

Congrats. Having a few spare triggers and triacs on board is good planning.

 

[JD5652]

It has been my experience that most often this symptom is the triac. However, I just the same symptom with a different root cause.

My AC system is comprised of 5 total compressors that operate off a single raw water pump. All AC controls have been updated to SMX II. Last week, my Master State Room compressor would not shut off... even if I turned the unit off from the keypad. The offending component was the relay contactor located in the large controls box with the breaker. The contacts on the relay had "welded" closed. I was able to break the contacts apart and recondition them (used a small nail file). The contacts were severely pitted. It is working for now, however I was able to order a replacement relay. See attached picture. The relay is located on the lower right hand side of the box.