I've lived in my home for 3.5 years, and I think the furnace was about ten years old when I moved in. I never had any problems until last week when it blew a fuse. I replaced the fuse, and it immediately blew again.
What could be causing this? What should I check?
My HVAC is giving my thermostat the silent treatment. Thermostat tells the furnace to get warmed up. Nothing. Tells AC to cool it. No response. They were getting along great just a few days ago.
I swapped out the newer Sensi smart thermostat for the old dumb one to see if the thermostat is the problem, but still no response.
Could this be a loose connection somewhere? Where should I look? Could it be something else?
Sincerely,
A Clueless Homeowner
Edit: It's not the wires in the thermostat. I took the photo when I was in the process of swapping out the new thermostat for the old one. All wires were screwed in tight, and I have the same problem with both thermostats. Based on what a few folks have suggested, I suspect it's a blown fuse.