Trane Split System Heat Pump Blowing Cold in Heat Mode
I have a Trane Split System Heat Pump that intermittenly blows cold on start up in heat mode. The Defrost Control Board and defrost thermostat was replaced a few months ago because it was freezing up in heat mode. And the technician replaced the reversing valve solenoid two weeks ago... it ran great but then began blowing cold on start up while in heat mode.
It is a Trane TWP042C100A1
What is outside temp?
Is compressor in outside condenser running? You should check if you don't know.
I probably would change thermostat setting to emergency heat.
Then call your HVAC dealer for service call.