Why Is My Furnace Not Heating?

If your furnace isn’t blowing hot air, you may be tempted to call for furnace maintenance. But before you do that, there are some things you can do yourself to figure out why your furnace is not heating or working correctly.

Thermostat Problems

You can get a lot of information about the state of your heating system by checking out the thermostat. Oftentimes, all it takes is a quick thermostat reset to get your HVAC system back on track.

Fan is Set to On

Make sure your fan is on auto mode. Too often we see thermostats in “fan” mode. When fan mode is set to default, the fan is always running—even when the home has reached its desired heat level. This means the fan will always be running, making your nice warm home cool again. When you switch the fan to auto, your HVAC system will go into a sleep mode once your home is nice and warm.

Somebody is Messing with the Thermostat

Not all family members like the same temperature. Some feel the cold more than others, and some get too hot quickly. Check that nobody is messing with the thermostat settings causing the fan to blow cold air.

Battery is Low

When a thermostat battery is low, the system will essentially turn off. The thermostat is like the remote control for your entire HVAC system, when it’s out of battery, so is your furnace.

Most people who own a thermostat have a good idea of how to replace the batteries in the device. However, if you don’t have any experience with electronics or aren’t comfortable taking apart the unit, it is best to call for professional furnace maintenance.

A Clogged or Dirty Air Filter

If your furnace is blowing cold air, you may have a dirty or clogged air filter. The easiest way to check is to remove the filter and replace it with a new one.

If you have a washable or reusable filter, you can clean it using a vacuum cleaner with a brush attachment. All other air filters will need to be replaced. We recommend changing your air filter at least twice per year. For homes in dusty areas, or homes with long haired pets, you may need to change the filter more often.

If your furnace isn’t working after cleaning or replacing the filter, you’ll need to call an HVAC professional to check on your system and preform any necessary furnace maintenance.

High Limit Switch Failed

Your furnace has several sensors that keep it running safely and efficiently. One of these sensors is the high limit switch, which detects excessive heat levels in the furnace and shuts off power if they get too high. When this happens, you won’t be able to use your thermostat or turn on any fans. The best thing you can do is call an HVAC professional to diagnose your system and reset the switch.

Clog in the Condensate Drain Line

Condensate drains are designed to remove excess moisture from indoor air during normal operation of a central heating system. The moisture is drained by gravity through the condensate pan, which is a flat pan that sits under the furnace.

A Problem with the Fuel Source

If you have a furnace that stops working, it could be because of gas, oil, or electricity.

• If your furnace is not getting enough gas to work, the pilot light will go out, and the burner will shut off.
• Check that you have enough oil in your tank.
• For furnaces that run on electricity, check your fuses, and power supply.

Leaking Ducts

A leak in your ductwork allows cold air from outside to enter your home through the ducts and mix with warm indoor air before being blown into other rooms through registers or grills in the ceiling. This causes uneven temperatures throughout your home.

Pilot Light Isn’t On

The pilot light is a safety feature that ensures your furnace doesn’t accidentally ignite in the off position. When the furnace is off, there is no flame to burn out a system component. If your pilot light goes out, a system problem needs fixing immediately.

Pilot lights are intended to stay lit for several hours after being ignited, so if you notice that yours has gone out, it’s time for furnace maintenance.

Burner Issues

A blocked burner can be caused by a buildup of dirt and grease. After a while, these substances clog up the burner, making it impossible for gas to ignite properly. This may also cause damage to other parts of your furnace, making it tricky to heat your home.

Flame Sensor Issues

A dirty or worn flame sensor will cause your furnace to run inefficiently, resulting in higher energy bills and possibly damaging your heating system. To clean the flame sensor, remove it from its housing and use a small brush to gently scrub any dirt or residue away. If the flame sensor is worn or damaged, you should replace it with a new one.

Always Call a Professional for Furnace Maintenance

A professional technician can collect data about your furnace to help diagnose problems or determine how best to fix them.

A furnace tune-up helps ensure your system runs efficiently and prolongs its life by clearing out dust and grime. What’s more, heat will reach parts of your home evenly, saving you money on heating bills!

Say goodbye to a cold home this winter by booking a furnace tune-up with the pros at Service Champions.