Furnace Control Board Fuse Keeps Blowing

Most of the time low voltage shorts are in the thermostat wires.

Furnace control board fuse keeps blowing.

If your furnace is blowing a fuse repeatedly leaving you with no power to the furnace your first step should be to call in an experienced hvac repair professional. 1 point 3 years ago. Here s how to diagnose a low voltage short. If the fuse blows when you have no low voltage wires hooked to the furnace then you have an internal problem like a bad limit gas valve connection or control board.

The coil in the contractor is 24v. When your furnace keeps blowing a fuse you need to take action quickly. It isn t the hsi inducer or blower motor as these are all high voltage parts not low voltage. Im going to show you how to fix this problem with just a screwdriver and maybe 5 3 amp fuses and we will fix the 3 amp short im just making this video for my.

I am guessing that you are referring to the fuse on your control board is blowing and not the high voltage fuse blowing. The contractor may be hanging up or shorting. Or just throw parts at it. Regularly tripping the fuse can be a fire risk because it indicates an electrical problem.

Amperage draw anything near the fuse rating would periodically blow a fuse. Assuming this is a fuse on the low voltage side coming off the 24 volt transformer it s possible the contactor in your condensing unit has shorted out causing it to blow the fuse. If you haven t been diligent about maintaining your furnace all its parts will have been silently and steadily collecting debris and dust. Furthermore i would remove all the control wires from the board.

Fuse on the circuit board blowing in your case you likely have a dead short somewhere in the wiring or a bad load that is going short to ground causing the fuse to blow. It s possible that the problem could turn out to be with your electrical system rather than the furnace itself but your hvac system is the most likely suspect so it makes sense to start there. Replacing the fuse or resetting the breaker can temporarily fix the problem but if the underlying issue is not fixed the fuse will just blow again. If it is a low voltage fuse problem then you have a low voltage short somewhere.

Make sure you have a good fuse and then reattach them one at a time.