Furnace Control Board Fuse

I did a recent service call and the 5 amp fuse in the circuit board on the furnace was blown.

Furnace control board fuse.

I turned off the input power and attached terminal r 24 vac power to thermostat and the fuse blew. I replaced the original control board with a honeywell st9120u1011 universal control board about two years ago after the original one blew. I was blowing the 5 amp fuse on the control board for my forced air gas furnace. Should i check amp draw on compressor and both fan motors.

Electric furnace thermostat control wire. This will blow the fuse on the control board causing the draft inducer to not start which then stops the rest of the furnace functions from working properly. When a valve is unable to open and close properly it can sometimes heat up causing an electrical short that blows a fuse. I removed all the wires going to my thermostat and it would not blow the fuse when powered on.

It isn t the hsi inducer or blower motor as these are all high voltage parts not low voltage. He just called and told me fuse is blown again. Furnace or ac control board troubleshooting. The guy has a new condensing unit installed last year.

Your furnace s control board has a separate fuse that protects it from getting too hot. Can you guys point me in right direction to figure this one out. Its just being used for cooling right now. If the fuse didn t blow it meant the.

My furnace is a concord model cg90ub. Here s how to diagnose a low voltage short. Cartridge fuse flat blade dual element time delay class rk5 250vac 125vdc 200a 7 1 8 l 1 9 16 dia. Electric furnace problems can be frustrating especially when they come at the worst time.

Every troubleshooting tip i found said to disconnect the w heat relay and r 24v supply terminals from the thermostat and jumper them on the control board. If you have a gas furnace one of the valves may be failing. If someone pokes around your furnace and isn t careful they may loosen wires from the furnace s wire frame causing them to short and blow a fuse on the control board. Is your air conditioner or furnace not turning on or p.

Diyers often try and handle things on their own. If the fuse keeps popping in your air conditioner you have a 24 volt short.