Nest Gen 3 Thermostat calling for heat in both heat and cool modes

[apearce]

Hey Guys.  I am on my second Nest Gen 3 thermostat that calls for heat in both Heating and Cooling modes.  The first time it happened, I had a technician diagnose it and he said the thermostat was bad and was sending 24 VAC in both Cooling and Heating modes.   I had it replaced on warranty and the new one seemed to cool for 10 minutes and was all of the sudden heating again.  I have confirmed the voltage between the blue (common) and orange wire at the heat pump reads 24 VAC in either Heating or Cooling modes.  I am able to get it to cool by disconnecting the orange wire at the heap pump.  Pic of wiring for reference.  Any ideas would be appreciated.

 

[Patrick_Caezza]

@apearce 

Do you have a picture of the original thermostat's wiring that you can post?

Can you post a picture of the terminal block on the control board in the furnace/air handler?

What voltage do you read between the orange (OB) and the red (Rh) wires?

Was it working correctly before the first thermostat failed or did it never work correctly?

[apearce]

Thanks for the help!

Original wiring included in attached picture.

Not sure about the board.  Would that be on the outdoor unit or the indoor unit?  Also, what mode should the thermostat be in to check voltage across the red and orange wires?  The original Honeywell (in this picture always worked.  When I installed the Gen 3, it was too cold outside and it would not let me run in cooling mode to test it.  As an update, another technician just left and confirmed the thermostat is malfunctioning.  We rebooted the thermostat as well with no luck.