Hello, I think I may be in over my head here but this forum has helped me a great deal in the past so I Thought i would try again. I have a ClimateMaster Tranquility 27 and starting today the compressor will not start. There is no error codes present on the CXM/DXM board. Everything seems normal but the compressor doesn't kick on. I don't even know where to start. I was hoping maybe someone could help me zero in if it's in fact just a bad compressor.

One other piece of information : I can hear a humming sound coming from the compressor like it's trying to kick on. But never does.

sounds like the compressor is locked up. There is like a 8 year warranty on those. Good Luck.

Have you tried shutting the breaker off then back on?

You need to call a geo HVAC company to ck it out. If it's under warranty so much the better. They can probably solve the problem in less than an hour. No....I'm not an HVAC company. People have to call experts in their business when they're not.

Thanks for all the replies and suggestions. I was able to trace the problem down to a bad capacitor. I replaced the capacitor and all is working now! Thanks again.