Question about Honeywell T8400c1099 Electric Heat/cool Thermostat 145793
Has been working fine till today. Noticed it was getting colder inside so went to adjust the thermostat and the screen was blank. If you turn it to AC it runs and if you turn the fan on it runs, it goes blank when you turn it to the heat setting. I removed the thermostat plate to inspect the wires and the thermostat itself, everything was tight, clean and together. I then followed the wires to the unit to assure everything was still connected and not damaged, fine again. Then took the cover off the furnace, to inspect the connections and motor, again everything is clean, connected and seems as it should be. I also check the breaker just-incase and of course it was fine. I don't know what else to check and I have been searching online for a couple hours getting no where fast. Also, for the responders who don't know the model, there is no battery to check in the thermostat and it is not programable. Just a simple digital temp display and an up and down buttons with two switches "system cool-off-heat and fan auto-on.
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