How Do I Know If My Furnace Needs Repair?
January 17, 2022
Maybe your furnace has been making a strange noise for a few days, or maybe your home just seems colder than you’re used to. How do you know if your furnace needs a repair?
In most cases, if you notice something strange, it’s a good idea to have a professional evaluate your furnace for repair. Ignoring a potential problem could result in an expensive repair or premature furnace replacement down the road.
In this article, we’ll walk you through some common problems you may experience with your furnace to help you evaluate whether support from a heating technician is necessary. Some common issues that could require a repair include:
- No heat
- Short cycling
- Insufficient heat
- Strange smells
- Strange sounds
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Furnace Has No Heat
If your furnace isn’t generating any heat, don’t panic—there are a few things you can try at home to solve the problem before calling a professional.
First, make sure your thermostat's settings are on “heat” and “auto.” If a thermostat fan is in the “on” position, it will continually blow air even when the furnace isn’t running (meaning the air it pushes out will be cold!).
If this doesn’t resolve the problem, check to see if you have a tripped circuit breaker. If the circuit breaker trips again after the reset, DO NOT reset it again. Instead, call a professional to evaluate the problem.
If neither of these solutions causes your furnace to start generating heat again, you should contact a service technician for further assistance.
Furnace is Short Cycling
Short cycling is when your furnace turns on and off repeatedly without adequately warming your home (or finishing a warming “cycle”). Short cycling is a sign that your furnace is overheating, a problem that can require repair in some cases. To pinpoint whether a repair is needed to correct short cycling in your furnace, let’s look at why furnaces overheat.
Why Do Furnaces Overheat?
For your furnace to work correctly, it must be able to draw in a continuous stream of cool air. This air keeps the heat exchanger, the component of your furnace that heats your home’s air, at a safe temperature.
When not enough cool air enters your furnace system, its heat exchanger can overheat. When your heat exchanger overheats, your furnace automatically shuts itself off until the heat exchanger has cooled to a safe temperature.
Once the heat exchanger has cooled, your furnace will turn back on. Unfortunately, it will eventually overheat and shut itself down again, resulting in short cycling.
How Do I Prevent My Furnace From Overheating or Short Cycling?
In order to prevent your furnace from overheating or short cycling, you need to ensure there is enough cool air entering the heating system.
You should avoid the following mistakes that will restrict the airflow into your furnace:
- The furnace has a dirty air filter. If your furnace’s air filter has dirt and debris clogging it, the airflow to your furnace will be restricted. If you haven’t changed your air filter in a while, this could be the problem. Ideally, homeowners should change air filters every 1–3 months.
- The blower motor has damage. The blower motor of your furnace is what pulls cool air in through your vents and pushes warm air back out into your home. If your blower motor is not working properly, it might not draw in enough air to prevent your furnace from overheating. A blower motor repair should be evaluated by a professional.
- Vents are closed or blocked. If your air vents are closed or blocked by furniture, there won't be enough airflow to your furnace. This issue has an easy fix—just go through each room of your home and make sure your vents are open and unobstructed.
Overheating not only causes short cycling, but it also uses more energy and increases your energy bills and wear-and-tear on the furnace, making it more likely you’ll have other problems down the road.
Your furnace might also short cycle if there is a problem with the ignition system. The ignition system is what lights the burners of your furnace, warming the air. If your ignition system releases gas but does not light the burners, your furnace will shut itself off to prevent a buildup of gas. Once the gas dissipates, your furnace will repeatedly attempt to light the burners, causing short cycling. If this is the case with your furnace, your ignition system probably requires a repair.
To summarize: If you notice that your furnace is short cycling, consider changing your air filter and checking your vents first. If the short cycling continues, it might signify a more serious problem requiring a professional repair.
Furnace is Providing Insufficient Heat
Similar to short cycling, above, if your furnace is providing insufficient heat, either there’s not enough air for your furnace to work with, or your furnace’s burners aren’t lighting correctly. Check your vents and air filters first; if the problem continues, a repair is likely necessary.
Furnace Has a Strange Smell
A strange smell coming from your furnace is another sign that it might be overheating. As explained in the short-cycling section above, your furnace can overheat for many reasons.
The most common reason your furnace might overheat is also the easiest to fix—a dirty air filter. However, if you’ve changed your air filter and checked your vents, yet you continue to notice a strange smell coming from your furnace, you should consult an HVAC professional.
Furnace Has a Strange Sound
Is your furnace squeaky, rumbling, or making another unusual sound? In most cases, strange noises from your furnace indicate that your furnace components are dirty, broken, or need oiling. A heating professional can identify the cause of the noise and whether a repair is needed to resolve the problem.
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With hundreds of 5-star reviews, you can trust Ranshaw to repair your furnace the right way the first time. For over 60 years, our highly-trained technicians have been repairing furnaces without shortcuts for Queens, NY homeowners. We provide our technicians with ongoing training on different furnace problems, education about different brands and models, and organized service vans so we can be sure to complete your repair on the same day.
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