I bought Ecobee Lite thermostat last summer and connected it properly to the furnace using C wire. Air conditioner worked without any issues. But no luck with the heat. When the furnace gets the call from thermostat the exhaust fan starts but no glowing on HSI. Asked my neighbor (HVAC certified) to take a look into this problem. He measured all voltages and resistance but did not give me any answers. Installed the jumper between R and W wires and furnace gets heat right away. After he installed the brand new thermostat with C wire - no luck. I called another tech and he said my thermostat (Ecobee) is broken. He installed the thermostat( simple one with batteries inside) without C wire (Rh and Rc have jumper) and furnace has heat. So I realized, before I switched to Ecobee my old LUX thermostat was operated without C wire. The furnace is 19 years old and the brand is HEIL.
Can someone give me some directions how to trace the problem? Would be possible even to resolve the issue and use smart thermostat?
I tried to eliminate C wire and even installed ecobee with the PEK - no luck.