hello. i am back again.

so i bought a multimeter finally, ( i got it for free from harbor freight.) i checked the voltages between different wires. there was no voltage at all.

i called a few repair person. it is probably that something is wrong in the wires or in the circuit board. i only installed the thermostat myself, i didn't do anything to the inside of the whole system.

now i wonder, is it because of something that i did? the thermostat worked fine during summer.

when do those wires, circuit board start to go bad?