Furnace Electrical Troubleshooting: A Short Guide

A guide for HVAC electrical troubleshooting. Sandium offers expert assistance for electric furnace troubleshooting and resolving electrical problems with air conditioners.

Updated on Oct 23, 2023
5 min read
Furnace Electrical Troubleshooting: A Short Guide

Furnace owners may face a multitude of problems, the most common among them being the furnace fuse blowing up once in a while.

When this happens, your furnace does not receive power. Many people experience this when they connect some extra lights or appliances in the house; especially if these are of low quality. But your HVAC system or electrical system could also be the cause for your furnace fuse blowing up.

Electrical problems in furnaces have multiple causes and fixes. You need to be able to do some basic troubleshooting to find out the problem and to decide whether you can fix it on your own or if it will need an HVAC technician.

Here is a short guide to addressing electrical problems and repairs in furnaces. 

1. Clogged air filter

If you have not been cleaning the furnace air filter regularly, a lot of dust and debris gets caught in it. This dust eventually ends up in the blower motor, causing the fuse to burn out due to overheating.

This can even catch fire and is very risky. In this case, you will have to replace the fuse, replace the filter and keep cleaning the system every few months.

2. Contact with water

Water can cause a short circuit so check for any leaks or drips in or near the furnace space. Repair these in time to reduce the risk of fire in the house.

3. Loose wires

Furnaces tend to vibrate a little while running. Over time, this can cause some wires to become loose. This can lead to a short that will stop the electric furnace from heating. Loose wires could be a little hard to find but regular inspection can help find these in time so that they can be tightened or replaced.

4. Unclean or incorrect fuse

Lack of maintenance on your furnace leads to all components being very dirty. A fuse that has not been cleaned in a while will have a lot of soot and grime collecting on it, not allowing it to connect properly.

Another reason for a short fuse is using a fuse of the wrong capacity. If the fuse being used does not have the adequate capacity to take the load of your heating system, it will go off. Get trained technicians to check the fuse and they will be able to spot immediately if the fuse capacity is causing a problem.

5. Bad or incompetent transformer

The electrical system of every building supports a particular voltage and a transformer is required to convert the voltage to the correct amount in order to run the ignition, controls and timers of the furnace.

If the electric transformer fails or is inadequate, the system will experience a short. Replacing the transformer can fix this problem.

6. Failing blower motor

A blower motor that is not functioning properly will end up drawing too much power and cause a short. You don’t want this to happen in the summer or during those cold Bay Area winters right there near all that cold Pacific ocean water. You can get an HVAC technician to replace the motor to fix the issue.

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