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After installing a Google Nest, my furnace heats until it reaches the correct temperature, but if it sits, the controller light turns off and I need to turn the breaker off and then back on in order for the furnace to kick in. The controller light turns off, but does not flash as far as I have seen. I have switched back to the original thermostat, some basic Honeywell one, and it works fine. There is a C wire connected, though I had to add that and I'm not sure if it's totally legit. Currently the C-wire is connected at the T terminal.

My furnace is a Lennox G14 series (I'm not sure which model exactly).

I am fine using the old thermostat, but I am bummed because I was looking forward to automating this stuff. Thanks for any help!

Wire diagram

Thermostat wires connected to furnace

Controller with light on

Correllion115
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1 Answers1

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The solution that seems to be working so far is adding a 1kOhm 5W resistor between W and T, that being the call for heat voltage. After contacting Johnson Controls, I was redirected to an engineer at Baso (which now owns this particular model of Johnson Control) told me that older controllers sometimes expect more of a load when heat is called for, and newer controllers have these built in.

Correllion115
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