When your home’s furnace is functioning as it ought to, you probably don’t give it much thought. However, you know exactly where to place the blame when you suddenly notice that your house isn’t heating properly on a cold day.

Furnaces are built to last for several years, but they still need some attention from time to time. It’s essential that they be properly maintained, and that frequently means asking a professional service technician to ensure that everything is in good working order.

Even with good maintenance practices, problems can still arise. Here are five of the most common furnace problems that you might encounter:

  1. No Heat
  2. Not Running
  3. Repeatedly Turns On and Off
  4. Doesn’t Turn On Automatically
  5. Makes a Lot of Noise

What do these problems mean? Even more importantly, how can they be fixed? Keep reading to find out.

1. No Heat

The primary function of your furnace is to keep your house warm when the weather is cold outdoors. This heat ensures that your family is comfortable and safe throughout the long, difficult winter. When the furnace seems to be failing at producing the necessary amount of heat, it’s only natural for you to feel some alarm. Fortunately, a furnace that isn’t producing enough heat isn’t necessarily the sign of a really big problem.

One reason why your furnace might be blowing air that doesn’t feel warm is that it’s running on the fan setting. The fan setting keeps air blowing through the house, but it does not heat up the air.

Furnaces also may not produce heat if the thermostat is turned off or if it is set to anything other than “heat.” It further is possible that the thermostat simply is set too low for the environmental conditions. Accordingly, if you feel like your furnace isn’t keeping things warm enough, one of the first things you might want to check is the thermostat to ensure that everything is at an appropriate setting.

A clogged filter is another common culprit that may be responsible for a furnace not producing heat. That filter is one of your furnace’s most important components. It prevents debris and dust from going through the ducts and into your home’s interior. The filter needs to replace on a regularly basis, with most experts agreeing that it needs to be changed at least once during the winter. However, if you have a lot of family members or pets in the house, then you may have to change your filter every month. A clogged, dirty filter prevents proper air flow from the furnace, which can make it seem like the unit isn’t producing enough heat. Simply replacing that filter might fix the problem.

If your furnace has a pilot light, it might be responsible for a lack of heat as well. When there is no flame, the fuel cannot ignite and warm the air. This is an especially prevalent problem in older model furnaces that have continuously lit pilot lights because these can go out. More modern furnaces are equipped with electronic ignition that ignites the pilot light whenever the furnace cycles “on.” Still, sometimes these ignition systems fail.

If you have looked at the pilot light, thermostat and air filter and still find that your furnace isn’t producing heat, then it may be time to have a technician take a look.

2. Not Running

You hear your furnace begin a new “on” cycle, then it suddenly cuts off. The room you’re in is nowhere near the set temperature. What’s going on?

Sometimes, this signals a tripped circuit breaker, but it also could mean trouble with the pilot light or a clogged filter. It additionally is possible that an unknown issue triggered the furnace’s safety switch and automatically shut it down. If you cannot find a tripped circuit breaker or a clogged filter, then it’s probably time to ask for help from a trained technician. It may be that an undiagnosed issue tripped that safety switch and needs to be dealt with.

3. Repeatedly Turns On and Off

You use your home’s thermostat to set a preferred temperature. It’s the job of your furnace to bring the rooms up to that temperature, and then maintain it. This is accomplished by running through a series of “on” and “off” cycles. Depending upon factors such as the desired indoor temperature and outdoor conditions, the furnace may turn on, heat the room to the programmed temperature, cycle off and then cycle on and off as needed to maintain that temperature.

However, something may be wrong if you notice that your furnace is running through really short cycles and doesn’t ever seem to hit the set temperature. A short cycle might only last a couple of minutes, and the most-frequent culprit behind this problem is insufficient airflow that causes the furnace to overheat. Modern furnaces are equipped with safety switches that automatically shut down the system if it overheats.

A clogged air filter may be the ultimate cause behind this problem. Check and replace it, if necessary. If this does not solve the problem, then you may need a technician to diagnose the issue.

4. Doesn’t Turn On Automatically

When it is functioning as it should, your furnace turns on and begins to produce heat as soon as it gets a signal from your thermostat. However, there could be a problem if the furnace stubbornly refuses to turn on. You may notice your home is starting to get cold. Surely there’s something wrong with the furnace.

It’s possible that you can find a quick fix with this issue, but you also may find that you need a technician to examine your furnace. Before calling in a professional, check:

  • The circuit breaker;
  • The air filter;
  • The thermostat;
  • The fuel supply; and
  • The pilot light.

A minor issue with any of these components, like a tripped circuit breaker or a clogged air filter, may be responsible for your furnace not turning on automatically.

5. Makes a Lot of Noise

Usually, the sounds that your heating system makes are part of the “white noise” of your home. You generally don’t notice every time the furnace cycles on and off. Likewise, you might become really accustomed to hearing the subtle click that’s made when the thermostat hits the programmed temperature.

However, a furnace will sometimes make other sounds that are far more alarming. If you are hearing a knocking or rattling noise coming from your furnace, this may signal that a component has come loose and is moving around in the unit. Tightening or adjusting that component may be the only thing that stops the noise.

A furnace that makes a rumbling sound might be struggling with leftover fuel in the combustion chamber.

Whether you are hearing knocking, rattling or rumbling, it’s time to turn off the furnace and call in a professional for some help.

A Quick Troubleshooting Guide

Most common furnace problems come down to a handful of possibilities. Things like the air filter don’t always get the attention that they deserve. Accordingly, if you are noticing that your furnace just doesn’t seem to be operating the way that you expect it to, take a look at the air filter. Changing that filter could solve all of your furnace problems at once.

Similarly, it’s easy enough to check to see if a circuit breaker has been tripped. All it takes is going to the breaker box to see if the switch for the furnace is flipped to the wrong side. Flip it back to the other side. If it stays on that side and the furnace begins running, then you probably don’t have a larger problem.

It’s also sensible to check the thermostat before you panic. Is the thermostat set to heat? Is the fan setting off? Is the thermostat set to the right temperature? The wrong setting can make you think that your furnace isn’t working.

When to Call Delaware Heating and Air

If you run through your troubleshooting checklist and things aren’t looking better, then it’s time to call Delaware Heating and Air. Our friendly and experienced technicians are exceptionally good at diagnosing furnace issues, and they can probably have your house warm and toasty in no time.