Furnace Control Board Has No Power

Measure from r to w.

Furnace control board has no power.

Heat mode goes strait to trouble code bad ground open ignition circuit also no power from board to induction motor. It is possible that the problem could stem from your electrical system rather than the furnace itself but your hvac system is the best place to start. With the stat in off mode. Either way check to make sure you have the proper input voltage to the board.

If you have 24 volts and no light on board. Next you want to check the output and this is a little more involved than the previous step. If your building s electrical system supports 120 volts your furnace needs a transformer to convert to the correct voltage to run the controls ignition and timers. In some cases this will be line voltage and in other cases the board will get its power from the control transformer.

Changed control board in gas furnace new board has no power to transformer blower motor lead on cool terminal hot all the time all the safety switches ohm out. You should see 24vac. If so it will need to be replaced. The sequence is like this.

Measure from r to c at the control board. Make sure the 110v power switch at the air handler furnace has not been turned off then see if the fuse on the board at the air handler is not blown automotive type then there is a safety switch. Furnace control board fuse keeps blowing 1 answers hi i have a carrier furnace 48gs 036090311tp with a honeywell t8401c thermostat. You have bad board replace it.

Check for 24 volts to board from transformer. The electric furnace transformer may be failing causing the system to short. Power up transformer cool mode works blower stays on after temp is reached. Don t forget when the blower door is open.

A model number of the furnace would be helpful too. You should see 24vac. If your electric furnace is blowing a fuse repeatedly when turning on your first step should be to call in an experienced hvac repair professional. The ac power is disconnected.

What would cause electric furnace circuit board to fail. Fan only operation is running.