Natural gas furnace with forced air. The furnace controls the fan.
Every time I turn the heat on I hear a click from the unit, but the thermostat will turn off - power cycle, and will just go into loop trying to turn the heat on and then reset. Getting it to stop is a hassle.
Deleted and re-setup the thermostat but didn’t help. Cooling work ok and so is fan. Old thermostat had jumper between RC-RH.
I was confused by the blue wire as well. It could be that somewhere around where the blue wire turns green there is some short going on between those two and other wires.
I assume, since you are using the C-adapter, the old thermostat was using batteries. If that is the case then it would not be affected by this short circuit. I’m not sure how much of an ordeal it would be, but I think the safest thing is to install a new wire.
Update: Replaced the wires, this time got 5: R,G,B,W,Y.
Re-setup the Thermostat, but still getting the same issue - as it tries to turn the heat on, the thermostat resets.
Since I didn’t have the Blue (common) before, I connected the new wire to the bare metal of the furnace. Is that OK ? it gives me the 24V as expected from the R and C wires. Should other wires also give me 24V ?
Hi, I had the same issue when I switched to an Ecobee. The cause was that the high temperature limit switch on my furnace was tripping and cutting power to the thermostat. My old thermostat had a battery backup so I never knew this had been happening the whole time. I had a tech come out and turn down the gas pressure and the furnace is no longer overheating and the reboot loop is gone. Not sure if that applies in your situation but thought I would throw that out there.
From what I can tell, it looks like the wire marked Y1 is the one that goes to the outside unit along with the red wire. The wire coming from the Thermostat should probably be connected to the Y1 terminal on the furnace instead, along with that wire.
Honestly, I am not sure. Mine looks very different with a fixed temperature threshold printed on it. Yours looks like it’s configurable. My understanding is that the limit switch shuts everything down when the furnace gets too hot, but may keep the fan running to cool things off.