Upon arrival, I found the thermostat blank. I went into the attic and discovered no power in the furnace. I proceeded to the main electrical panel and located a tripped breaker. I reset it and found that the switch in the attic was off. I turned it on and got power back in the unit. Customer needs to replace 16x25x4 filter. I cycled the heating 2 times and ensured it was going to work and satisfy the temperature demand. Customer is unaware of when the issue happened. From what I can deduce, is that the flue likely got blocked by ice and tripped the system. System is heating inside of manufacture specifications upon departure.
