Furnace fuse blown: The facts you should know.

     A fuse in an electric circuit is a device which is used as the protective device. There are many types of fuses used in the electrical world. 

Table of Contents:

1. How to tell if furnace fuse is blown?

2. Why furnace fuse keeps blowing?

How to tell if furnace fuse is blown?

    You should be quite sure that you are addressing the correct issue before you head out to the nearby electric store to buy a new fuse. It only takes a few minutes of your time to become familiar with the simple and basic method of checking your fuse.

    Make careful to stop all electricity flowing to your furnace before you do anything else. Either the main electrical panel or the subpanel designated especially for your furnace might be used for this.

Visual inspection:

    Some fuses will have a cylindrical transparent glass body with a metal wire or strip running through. Some plastic fuses will have the same wire in which the wire is only visible when viewed from the side. On either type of fuse, we can tell that it is blown when the wire strip is broken.

Fig: Fuse status(Ref.-fuse-box.info)

Check by multimeter:

    If the metal fuse wire is not visible then we have to use the multimeter to check it. By measuring the resistance across the fuse we can check the fuse healthiness. If the fuse is good, there will be almost no resistance; otherwise, there will be no reading.

    Once, you know how to check your furnace fuse, you can replace it easily. However, you need to make sure to get the same rated fuse as before.

Why Furnace fuse keeps blowing?

    If you replace the fuse once and it blows again immediately, you have a considerably larger issue on your hands that needs to be taken very seriously. This can indicate an electrical issue, which puts you at danger of a serious fire. Before you damage the furnace, you must identify the source of the blown fuse on the circuit board. Here are some of the most typical issues:

Overload:

    This is among the most frequent causes of blowing furnace fuses. The furnace consumes a significant amount of electricity to operate, and your home could not be equipped to handle it or there can be a fault in the wiring. If you have reset the circuit breaker and replaced the fuse but the problem persists, you should contact an expert to inspect the system.

Short circuit:

    This is very common issue in any electrical system. If there is any short circuit in your system it will burn the fuse without any time delay. Therefore, before reinstalling the new fuse you must remove the short circuit fault.  

 

Fault inside the system:

    The burnt furnace fuse may occasionally be merely an indication of a significantly more serious problem with the furnace. Fuses that keep blowing can often be caused by a faulty transformer or a faulty thermostat link. Blown fuses are typically caused by loose wires in general. Make sure to inspect the connections because they may become loose over time as a result of the system normal operational vibration.

Under rating fuse:

    There is a possibility that the fuse installed is not the right wattage.  If you have had to replace them in the past, you might have selected a wattage that was too low for the demands of the furnace. For instance, A 3-amp furnace fuse could not be high enough. Make sure replacing the existing fuse with one that has a greater rating may solve your issue.

Clogged air filter:

    Many people fail to change their air filters on a regular basis? These filters could accumulate dirt, pet dander, dust, and other particles over time. All of these debris get inside the blower motor which causes the motor overload as a result burn off the fuse. It's possible that you can swap out your air filters and replace the fuse at the same time to solve the issue. Of course, it may leads to burn out the blower motor if there is not proper protection.

Water:

     If the fuse comes into contact with even a few droplets of water from any source, it will undoubtedly blow. Examine the vicinity of your furnace for any potential water leaks. Water may also cause severe short circuit fault in the system.

    You can always try to change the fuse on your own first for any of these issues. This is a fantastic first move that could help you save a ton of cash. After all, replacement fuses can be purchased at any electric stores for just a few bucks. If the subsequent set of fuses likewise blows rather soon, you might wish to contact a specialist. The potential risk and damage that could result from regularly changing the fuses simply isn’t worth it.