Nest appears to be working properly , however heat is signal is permanently. I had to disconnect white wire to stop furnace . I did reset set nest twice but still same symptom. Even removing nest from base there is till have a closed heat circuit .
Thank you for your response.......... There is no C wire ............This nest has been in use for a few years. Problem started with the furnace gas valve "Not" opening upon start-up .Control Board was changed in the furnace, furnace fixed............. Now did the old board somehow damage the nest? In the base of the nest the circuit is still closed signaling for heat. Does the nest have a relay in its base that is stuck or burned closed?