3 Signs Of A Faulty Furnace Capacitor


A capacitor provides the electrical energy needed to jumpstart the fan motors of your furnace. With a faulty capacitor, your heating system becomes extremely hot on the inside. As a result, the safety switch trips, which causes your furnace to shut down. So, your home stays unheated until a professional replaces the furnace capacitor. 

Learn some signs a defective capacitor exhibits before your furnace shuts down. 

Short Cycling

The capacitor should be in the best shape for your furnace blower motor to run efficiently. Sadly, a bad capacitor can't store the charge needed to power the blower motor. Consequently, your bower motor runs slowly and overheats, which opens the limit switch to avert an electrical fire or further damage to your furnace. 

Short cycling causes your furnace to work strangely or turn on and off on its own rapidly throughout the day. While low airflow and contaminated air filters in your furnace can cause short cycling, a bad capacitor is a good place to start if you're not sure where the problem is. 

Short cycling wastes energy (as evidenced by high power bills) and raises the chances of equipment breakdown. So, you should bring in an HVAC professional to test your capacitor right away if you notice a short cycling issue.

Humming Sounds

The sounds your capacitor makes when you turn on your furnace can tell you if your unit is faulty. A single-click sound when your furnace kicks on is normal. However, if you hear a humming sound or your furnace hesitates to start, then your blower motor capacitor may be about to fail. 

The humming sound is due to an electrical issue with your capacitor. A defective transformer, a faulty inducer motor, or an aging blower motor can also cause humming sounds. To know if a bad capacitor is to blame for the sound, turn up your unit's thermostat, then wait for your furnace blower to get started. 

Then, open your furnace access panel with a screwdriver and listen for a loud humming noise. If the humming sound doesn't stop, you definitely have a capacitor issue. You should call your heating system contractor to diagnose and repair your heating unit. 

No Power or Heat

With a broken furnace capacitor (due to dust, debris, or loose components), the blower motor will not function. For this reason, your furnace won't start at all. But before you blame it on a bad capacitor, first ensure the furnace fuse is on. 

After your furnace kicks on, turn up the thermostat by several degrees. If the blower motor doesn't respond after a few minutes, you may have a failing capacitor that an expert should look at.  

If you notice these capacitor problems, act fast before your furnace fails and leaves you in the cold. Contact a professional who provides heating services to test your capacitor and determine if you need to repair or replace it.   


4 January 2022

Cool off Your AC Bill

Every summer, I agonized over energy bills that would shoot into the stratosphere as a result of my efforts to keep cool in the heat. Every time I turned the temperature down, my bills increased. This summer, I decided to take some of the control over my energy bill back. I installed reflective film on my windows that reduced the amount of light and heat coming into the house. I started serving more cold meals or asking my husband to barbecue outside, so that my air conditioner didn't have to compete with the hot stove, and I started doing laundry at night to reduce appliance heat in the house at peak times. I also had ceiling fans installed. So far, the difference in my bill has been tremendous. This blog is a way for me to explore other ways to reduce energy drain during the summer months.