I have a heat-only electric furnace. Bypassing the thermostat, the R and W terminals on the control board are always connected. The thermostat is good but something is causing the control board to always have a low setting on the Fan and heater.
I have replaced the 240 and 24V relays and that did not fix anything. What could cause a constant ON even with nothing connected to the control board?
BREAKER OFF & no thermostat connected: Control board is not shorted, all terminals do not beep with multimeter continuity test
BREAKER ON no Thermostat connected: fan turns on, heating elements have 125V on them, all control board terminals beep and multimeter claims continuity between them.
Voltages: R to GND ~ 13V; W1,W2,G,C to GND ~30V