I have 1992 Sea Ray Sundancer on the Tennessee River. It is a marine air system self contained I think. Unit is located under setee. Last nite I woke up cold and noticed that the temp read 58degrees on my digital control and the unit was blowing cool air. I attempted to adjust thmostat to no avail. Checked connections all seemed ok. The compressed would cut on but no warm air from output. I replaced the short fuse, I think it said it was for reverse cycle. I had let it set 15 minutes while I went to ship store to get fuse. They only had a 4 amp instead of the 5 so I tried it anyway since it was lower I figured . I then turned on the unit and it began to emit warm air. After a few minutes the compressor was warm to the touch but not hot as it had been before. Watched it for a bit and I noticed it would cycle but the readout on the control unit seemed to drift up and down. From lower 60 to upper 70. The temp outside was 48. I shut unit down and came home to find info. I am returning later today. Any imput or things to check would be helpful.

I wrote down some numbers from the bottom of the info panel 204 3001 followed by what looked like a zero that had been filled in and a zero with a line in it then in the next box a 2-13315. It is a Marine Air Systems unit. There was water flow about the same as usual shooting maybe three inches from thru hull. I would have to estimate the water temp at around 45 degrees. If you will let me know what and where to look for the specific info you would need let me know and I can get it when I go back to boat this afternoon.

Thanks I will get info from boat and accurate water temp.

Changer to correct fuse. It has stopped readout movin up and down. Seems be cycling a lot. Small penguin facing away from logo. Says environmental control unit at top of control. Water temp 49 degrees

Ok…That all helps…Thanks 

Since that is a ECU control that does not have a temp sensor in the display (like later Passports)

I would locate the temp sensor end & make sure you have not developed a duct leak that is allowing discharge air to blow or leak onto the sensor….This will cause it to short cycle because with the unit running warms the air & it will see that…Then when it shuts it off it sees the air cool quickly & thinks it needs to turn back on…

Another reason to short cycle is the high pressure switch cutting it off & back on…This can happen for the same reason…Hot air leaking out of the discharge duct back into the return air, thus causing the unit to run high pressure…

Steve~