AC Compressor Always On

[stormchaser]

Turned on the AC when I got home. It was about 80* in the salon. I set the thermostat to 68*. Sitting in the salon with the AC set at a nice cool 68* and realized I was getting COLD. Look over at the thermostat and it is 65*F I turn up the temp to 70 and the air is still blowing cold. I check the engine room, sure enough the compressor is still on. I turn OFF the AC at the thermostat switch and the blower stops but the compressor keeps running. I turned it off at the master breaker and let it sit for a couple minutes and flipped the switch...compressor came right back on. It seems like no matter what the controls are set to, the compressor comes on. I did put it in heat mode for a second and it did flip the reversing valve but still stays on eveb with the thermostat/controls turned off. The only way to get the compressor to cut off is to kill the power to it. Thoughts?

 

[stormchaser]

One interesting thing to add to the puzzle. Turn it from cool to heat and the reversing valve instantly kicks in. Change it from heat to cool and it takes up to 30 seconds to make the switch.

 

[MikeP]

Do you have the oem knob controls or a digital replacement? I had the exact same thing happen last year and it turned out to be a bad Coastal Climate FX1 Box. I had to buy a new box to fix the problem. There was actually more to it than just buying the box but if you don't have the FX1 control, there's no reason to get into the "rest of the story."

 

[stormchaser]

Ugh, I have the digital controls. Everything except the compressors was replaced when I bought the boat so I could have aux heat.

 

[SKYCHENEY]

Its a bad triac.

 

[stormchaser]

To clarify, I have the SMXht Control System from Cruiseair.

 

[stormchaser]

Its a bad triac.

A what?

 

[chris piazza]

A triac is a trigger or "relay" found on the panel for the CC. The relay is stuck closed which keeps the compressor running.

Chris
Superior Nights
53C

 

[sdowney717]

If true what you could do is replace the triac with a new one. It is likely soldered on the board.

 

[MikeP]

The Triac was what was suggested for the problem I had as well but it tuned out to be the FX1 box, the Triac in the oem Cruisair Box was fine. Hopefully, in your case, it IS the Triac since it's an easily (and cheaply) replaceable item.

 

[stormchaser]

Is there a test I can do on it? Like jump around it to test or anything like that? I don't suppose anyone can tell me what to look what it looks like? And which box it would be in? I'd LIKE to try to fix myself if it's not too complicated.

 

[MikeP]

Here's a quote from SPcoolin who had a website re marine ac work. Sadly, he passed away last year. But this quote may be useful. It was an answer to a similar problem:

"Sounds like the SMXII controlled unit/s have bad compressor triac/s (solid state relay)
To test this…Make sure the SMX is off (No Fan running) Then go to the engine room & see if the compressor & pump are running…If they are…Shut off the breaker….Don't run the systems till you get replacement triac/s as they will likely ice up which is not good for the compressor…Either that or cycle off the unit with the breaker till you get the part/s…You really don't want it/them running without the fan/s
The replacement Triac part # is A-548 and sells for $40.00 ea…Two screws & 3 wires (push on) each to replace…It looks like a black half of a Domino and is fastened to the inside of the box with the circuit board in it…Wires should be Black, Purple, and a smaller Yellow…."


Here is the link to his website which was superb: http://marine-ac.com/forum/ You may want to do a search on it for additional info.

 

[stormchaser]

Here's a quote from SPcoolin who had a website re marine ac work. Sadly, he passed away last year.

OMG! He helped me in the past! I had no idea he was gone. Now I'm sad...really nice guy.

Which box would this be in? I don't suppose anyone who is on their boat and knows what to look for would take a quick pic?

 

[stormchaser]

And I wonder if it's OK to run as is? Even after several hours of constant running and the room temp dipped to 64*, there was no ice buildup on the outside of the compressor...but it was DRIPPING with condensation.

 

[stormchaser]

For future reference in case anyone searches for this...here is the thread on this problem from his website: http://marine-ac.com/forum/troubleshooting/compressor-stays-running/

 

[stormchaser]

here's how to test:

Another way to confirm they are bad is to remove the yellow gate wire from the triac…Then turn on the breaker…If it still runs the compressor/pump, then they are for sure bad…

If compressor/pump shut off with the yellow wire disconnected from the triac then we have another problem…Likely the board itself…

 

[SeaWhisper]

Triac should be located in a 5"x5"x2" box within a foot or two from the ditigal control panel. Had a new compressor installed last month and the system would jump to heat mode on start up, triac was the problem. Price about $40.00

 

[stormchaser]

Near the control panel? I thought all of my boxes were in the engine room that has the compressors? If not, the unit is the salon one and the control panel is mounted to the aft wall on the starboard side. The blower unit is in a built in end table that also houses the stereo on that same side. Would it likely be in that somewhere?

 

[Pascal]

Probably. All my digital controls have a display connected to a control box close by. Usually mounted in the same hole/cabinet as the air handler

 

[SeaWhisper]

Probably. All my digital controls have a display connected to a control box close by. Usually mounted in the same hole/cabinet as the air handler

I agree... mine are setup the same way!