Furnace Control Board Blowing Fuses

When a thermostat wire touches the metal frame of the furnace it can deliver more voltage than the wires are designed to handle.

Furnace control board blowing fuses.

The 5a fuse that is blowing is a control fuse for the 24v control side of the system. Many times the thermostat wires will short out against the body of the furnace or air conditioner. 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. The most probable of these are 1.

Furthermore i would remove all the control wires from the board. 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. If you haven t been diligent about maintaining your furnace all its parts will have been silently and steadily collecting debris and dust. 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.

Your furnace s control board has a separate fuse that protects it from getting too hot. We have a really good tool that you can use to save fuses when troubleshooting low voltage shorts called the lil popper. Loose electrical cables there could be loose electrical cables inside the circuit box or somewhere in your ac which could be causing a short circuit. Electric furnace thermostat control wire.

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. But for those who ve recently encountered one common issue a furnace blowing its fuse before scheduling that tune up it may be due to one or more of the following reasons. Make sure you have a good fuse and then reattach them one at a time. Pay close attention to where the thermostat wires where the wires go through the body of the furnace or air conditioning unit.

If someone is poking around your furnace and is not too careful they could more wires so that they come into contact with the furnace s wire frame causing them to short and blow the fuse on the furnace board.