For this evaluation the customer stated her system was only cooling even when set to heat and with the temperature set to 78⁰. Then randomly the system stopped responding at all. I turned the thermostat off and manually jumped the system to bypass the thermostat however the reversing valve had constant voltage, even with a call for heat so it is only cooling. This indicated the thermostat is the culprit and sending a constant call for cool. I replaced the thermostat under warranty with a new one and the system started working like it should.