Marine Air(dometic) passport II AC compressor cycling

[phorvati]

I wanted to give an update. None of suggestions thusfar pointed in the direction of run capacitor. I did some searching and compressor cycling is a symptom of a run capacitor failing.
I looked up the part and AM Rad engineerig makes mine. It was made in 1990. Was able to buy the same part number capacitor for 25$ on ebay. They are american made. These capacitors are labeled 25.0 MFD. Which is so misleading. It would inidicate millifarads, which in terms of size and voltage rating would be a reasonable capacitance for this component. Well its actually 25uF as in microfarads. I have an RLC meter at work and after getting a brand new capacitor, i measured capacitance at 100Hz for old and new capacitor. So new one was 25uF which is what is supposed to be, but old one was 10pF. Thats gone down by a factor of a million. No wonder my compressor was cycling. Run capacitor has failed had no capacitamce left. What would one expect after 30 years. I havent put it in yet, but I feel pretty good about my chances of this beeing the root cause. Here is a pic of the twp side by side

[Heath68]

Originally Posted by phorvati

I wanted to give an update. None of suggestions thusfar pointed in the direction of run capacitor. I did some searching and compressor cycling is a symptom of a run capacitor failing.
I looked up the part and AM Rad engineerig makes mine. It was made in 1990. Was able to buy the same part number capacitor for 25$ on ebay. They are american made. These capacitors are labeled 25.0 MFD. Which is so misleading. It would inidicate millifarads, which in terms of size and voltage rating would be a reasonable capacitance for this component. Well its actually 25uF as in microfarads. I have an RLC meter at work and after getting a brand new capacitor, i measured capacitance at 100Hz for old and new capacitor. So new one was 25uF which is what is supposed to be, but old one was 10pF. Thats gone down by a factor of a million. No wonder my compressor was cycling. Run capacitor has failed had no capacitamce left. What would one expect after 30 years. I havent put it in yet, but I feel pretty good about my chances of this beeing the root cause. Here is a pic of the twp side by sideAttachment 281247

Following..

[phorvati]

So far so good. I ran it on 3 occasions but all less than 1 hour. Twice in heat mode and now AC. But I'm reluctant to declare victory just yet. Tonight, admiral and i are sleeping on the boat and heat will be needed in RI.
Its not as hot and humid during the day so this is hardly a stress test. I had a lot of cycling in the spring in heat mode but perhaps because ocean was cold and we needed heat.
Im affraid even in heat mode with ocean still warm, it will be producing heat, again without a real stress.
But at least i can say that in 2 hours so far, no cycling.

[phorvati]

So i ran the my AC, vector compact Vcp16k in heat mode extensively. As in 6 hours overnight and 4 hours during the chilly and rainy day. I did have some cycling which still bothers me so i would not call this a home run, but definitely signifficant improvement.