Goes from cool to hot

Bill Texas

I have a trane unit model #BWD748A100A0 a tech replaced the thermostat (thermostat keep burning out approx two so far) and the unit on the air handler where the wires from the thermostat attach been replace and the orginal problem it goes from hot to cool,shut the Unit down and back on to cool .Is there an control panel on the outside unit (Evaporator)? could the problem be in the wiring?

biggles

is there a wire connected to the C terminal on that subbase for the stat?the outside part "condenser" should be a pair going out from the air handler if it isn't a heat pump.burning up stats and boards is a major install problem...is the stat set in auto if so only run it in cool system and fan auto see if that locks the heat out....if your still geting heat still needs to be looked at...what is the heating setting on that stat anyway?

scottmcd9999

That's a heat pump, so you'll have more than two wires. It's entirely possible that you've got a wiring mixup causing the reversing valve to activate/deactivate at times, which would cycle you between heat and cool.

There is a defrost control system in that unit, but I'm not sure if it's mechanical or electronic. If it's electronic then you could certainly have issues with it, which could cause the same issue.

Sounds like you need to find a tech who will troubleshoot the entire system, and not just swap stats.

Bill Texas

when on the outside at the unit the compressor start making a noise and shut down the fan continue to run , inside of the house warm air and a few mins later the compressor came back on and start to cooling .