I was just pottering about in the garden and realised that my air con compressor was running.

Nobody has turned the wall unit on inside the house and when I did so because it wasn't open it shot out a big puff of cold air and is full of water due to not expelling said air.

I don't think it has been running for long because the outside unit isn't that warm.

What would cause the compressor to start up on its own accord ?

It turns off only when I shut the breaker inside the house.

If I open the breaker it turns on again but not the inside unit.

The unit has not been run daily for sometime as the weather has been cooler up where I am.

The last time it was turned on was about 10 days ago just to give it a run up.

Any ideas this has never happened before,the unit for all its worth is a Mitsubishi econo air Mr Slim 18000 BTU and has been well maintained every year with regular cleaning etc.

Have had happen - I called air conditioner repair and they found problem easily but do not remember what it was.

Had the same thing a couple months ago: relay was stuck open/closed forget which - did it all by itself after a low voltage session. About 1K baht to wit to replace.

Does sound like a stuck motor relay, unless you know what you're doing call the man in.

Thanks for the replies,I will get my guy in to take a look.

Got the solution ?