Furnace Blower Motor Hums But Won't Start? (We Have A Fix)

A good functioning furnace is essential, especially in the colder months when you want to warm up your home to keep cozy. However, it can be frustrating if your furnace won’t cooperate. It’s pretty standard for furnace blower motors to have issues, but what if the blower motor hums but won’t start?

If your furnace blower motor hums but does not start, this is most likely due to a faulty capacitor. To ensure the capacitor is the issue, you will need to test the capacitor itself before you replace it. This can be done quickly by yourself or by hiring a professional.

This article will talk about the signs of a bad capacitor and how you can diagnose the problem without contacting a professional. Moreover, we’ll provide instructions on how you can test your capacitor to ensure that this is the problem.

Humming but refusing to start is not an uncommon problem with furnace blower motors. Most likely, the capacitor is the culprit. This is a small and inexpensive electrical component that’s not difficult to find and replace.

However, a faulty blower motor is another possibility. That would involve more expense, but we’ll start with the capacitator as it’s less common.

There are two kinds of capacitors: Start capacitors and run capacitors. Most newer furnaces only have a run capacitor. Dual-run capacitors found in AC condensing units and packaged heat units run two fans simultaneously – for example, the blower fan and the AC fan.

The most cost-effective way to replace a capacitor is to use a quick DIY fix. If you don’t feel confident to carry out the work, a contractor will, of course, involve more expense.

The fix is relatively easy and friendly for DIY beginners. If we had to rate this on a scale from 1 to 5, with five being the most difficult, we say it’s about a 2.

However, the difficulty depends on what needs to be removed to allow you to access the capacitor bracket. In specific models, it’s immediately accessible. In others, you’d need to remove a panel or control board.

If you already have a multimeter and want to be certain that your run capacitor is at fault, it’s quite simple. Just follow the steps below. However, before you go any further, just a word of caution. As we previously mentioned, the run capacitor stores up to 400 volts of additional energy.

Please pay close attention to Step 1 below to avoid an electric shock. It’s also understandable if you prefer to leave this work to a professional – it will ensure no accidents.

The price will typically be anything from $5 to $20. It’s worth bearing in mind that your capacitor may fail at some point.

It makes sense to invest in a spare (and also an extra igniter) so that in case of need, you can replace it immediately. While this isn’t necessary, most people find it convenient not to scramble to locate the part they need.

To have a furnace capacitor installed by a qualified HVAC technician can cost anything from $80 to $200. Expect a minimum fee of $75, even though the part is inexpensive and the repair can be completed between 5 -20 minutes.

If you need the repair carried out at night, or the weekend, expect to pay more. If there’s no danger of additional damage due to frozen pipes, it will save you money if the repair is carried out during regular working hours.