Furnace Control Board Has No Power

Furnace control board fuse keeps blowing 1 answers hi i have a carrier furnace 48gs 036090311tp with a honeywell t8401c thermostat.

Furnace control board has no power.

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. If so it will need to be replaced. 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. First make sure you have power to the board.

You should see 24vac. 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. Measure from r to c at the control board. Just went thru the flow charts from rheem on that furnace.

The sequence is like this. Don t forget when the blower door is open. What would cause electric furnace circuit board to fail. Fan only operation is running.

The ac power is disconnected. The electric furnace transformer may be failing causing the system to short. If you have 24 volts and no light on 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.

With the stat in off mode. Measure from r to w. 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. I can run the fan on continuously but when i put the heat to on on the t stat the 5 amp fuse on the control board lh33wp003a in the furnace blows. Heat mode goes strait to trouble code bad ground open ignition circuit also no power from board to induction motor. Next you want to check the output and this is a little more involved than the previous step.

You have bad board replace it. Either way check to make sure you have the proper input voltage to the board.