How to Change a Furnace Fuse

When changing a furnace fuse, check to see if it has burnt out, and if it has, simply find a fuse of the same style to screw back in its place. Turn the power off to work on the furnace fuse that exists on the circuit board with help from a plumber and HVAC tech in this free video on furnace fuses.

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Video Transcript

You may run into this problem, you've got your furnace, you turn on the thermostat, you get nothing. A lot of times it could be an electrical problem. Now if you come to a furnace such as this, this is where you turn the power on, of course. Now this one is set up with a fuse, it's a safety fuse. Flip this up, now to replace this, very simple, you un-screw it. You can check it, and a lot of times you can tell if they are burnt out or not, but other times you can't. So your best bet is find the same style fuse, this one is a bus fuse, twenty amp. Find yourself another fuse, screw it back in, try it again. Make sure that when you are replacing this fuse the power is off. Okay you have one other fuse that is built into your furnace, and this is on the circuit board. Now to get to the circuit board, of course, turn the power back off, we're going to pull the doors off. The top door just goes to your blower motor, not a real big deal, you are not going to get injured by this, because there is a safety switch inside here. With this door off it shuts everything off so you don't have to worry about getting hurt. On the board of this furnace you always come to another bus fuse. Similar to a car fuse, very easy to replace, but this can be shorted out by the easiest things. If your thermostat wires touch together it's going to blow that fuse, it's a very common problem with a furnace like this. You blow your fuse, put a new one back in. Of course, there is nothing wrong with this one, just demonstrating. Put this back in, and make sure you put the doors back on first, because your furnace won't even try to fire without it. Put your doors back on, then you go through the cycle and you try it again. If that don't work you're having a more technical problem, you might want to contact more of a professional.


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