Cruisair problem Air conditioning

[njamesphoto]

Hi, we have a cruisair self contained air conditioning unit on our boat. It was working fine. We did try it on the heat mode that i dint think its been on before. The unit is a 1990 vintage. The fans fun the start relay clicks but the compressor will not start. Occasionaly the compressor will start, works and then seems to get quieter and after 40-60 seconds the compressor stops. There are three knobs on the control panel, its recently been gasses and thats ok. would it be the start or run capacitor? I did remove them and they are showing open circit. We are currently in Barcelona and the temperature is 32 celcius with two small children aboard, any ideas?

 

[grumpy_o_g]

It could be the start capacitor but unfortunately you won't learn that much about the state of the capacitor with a digital multi-meter. If you have an old Avo or similar moving coil or moving-iron volt-meter then, on a reasonable size capacitor, you should see it start as pretty much short circuit and then gradually go to open circuit. (general warning - only try this is if you're sure the capacitor is man enough to take the voltage/current from the meter).

It certainly sounds like a capacitor breaking down - heat will exacerbate the problem if it is breaking down but 40-60 secs is a bit quick for it to be getting hot.

If you're feeling brave it may be worth a try taking the start capacitor out of circuit and seeing if will still start - perhaps help it a bit by spinning it by hand or ease the load in some way if you can. If it starts and keeps running it's most likely the capacitor.

I can't guarantee that this won't cause damage elsewhere in the unit but it would seem unlikely.