Your furnace is an integral part of your home. Without one, you wouldn’t be able to stay warm during cold weather. Yet furnaces can have some issues that are more common than others.

Let’s review these problems and discuss what they might cost to correct so you know before you call an HVAC technician. Some of the most common furnace repair issues include:

  • Furnace won’t turn on
  • Furnace doesn’t stay lit
  • Furnace won’t blow hot air
  • Furnace won’t turn off

1. The Furnace Isn’t Turning On

There are a few reasons why your furnace won’t turn on, so make sure to go through all of them.

  • Is your thermostat set right? Make sure it’s set to “heat,” “auto” and that your preferred temperature is higher than the room’s current temperature. If you use a programmable thermostat, make sure it has new batteries.
  • Is the circuit breaker tripped? Your furnace can’t operate if it doesn’t have power. Reset the switch if it’s facing the outside of the electrical panel.
  • Is the furnace switch off? Your furnace has a power switch found on or near it. Since this switch resembles a light switch, it’s easy to accidentally turn it off. If it was off, it may take your furnace a few minutes to turn on.
  • Is the air filter clean? A dusty air filter can create a lot of issues for your furnace. Get a new one if you can’t see light through it.

Estimated Repair Cost

This problem can be complex, so the estimated cost to repair it depends on what’s wrong.

2. The Furnace Won’t Stay Lit

Your furnace follows a specific sequence when it starts heating your home.

  1. Your thermostat detects the temperature has fallen and tells your furnace to turn on.
  2. The draft inducer fan activates to pull in fresh air for combustion.
  3. The gas valve unlocks for the burners, which are lit electronically.
  4. The flame sensor tells your furnace the burners have been lit.

If something is wrong during the sequence, your furnace will shut down as a preventive measure.

A couple of possible causes for this problem include:

  • Dirty or malfunctioning flame sensor. If the sensor doesn’t sense a flame, it will turn off your furnace to prevent natural gas from getting into your home. The ignition process corrodes flame sensors over time. While cleaning during annual furnace maintenance can help, yours may ultimately need to be replaced.
  • Bad limit switch. This safety feature will turn off your furnace if it detects backdrafting. Backdrafting is hazardous, because carbon monoxide and natural gas can seep into your home. These switches can malfunction due to age, damage or dust buildup.
  • Old thermostat. If your thermostat isn’t working correctly, your furnace won’t be able to run.
  • Dirty air filter. A dirty air filter can limit airflow and cause your furnace to shut down to prevent overheating. Make sure to replace yours every 30 to 90 days, or whenever you can’t see light through it.

Estimated Repair Cost

These costs are estimates, so it’s necessary to note yours may fluctuate based on your furnace’s brand and model.

  • Flame sensor: $350–$500
  • Limit switch: $150–$300
  • Thermostat: $150–$350
  • Furnace filter: $10-$30

3. My Furnace Is Blowing Cold Air

In many instances, this problem is linked to an incorrect thermostat setting or a dusty air filter that’s limiting airflow. Follow the steps above to resolve the issue.

4. My Furnace Can’t Stop Running

If it’s very cold outside or you like your home to be warm, your furnace may be working for a long time.

If this isn’t the case, make sure your thermostat is set correctly and working properly. If your fan setting is at “on,” the blower motor will be running even when the furnace isn’t, so it’ll sound like your furnace is on all the time.

Alternatively, there might be an issue with the blower motor or your ductwork may be leaking air, forcing your furnace to run continuously to make up for the air loss.

Estimated Repair Cost

These costs are approximations, so it’s necessary to note yours may be different based on your furnace’s brand and model.

  • New blower motor: $250–$800
  • Seal ductwork: varies based on house size

Bell Mechanical Services Can Get to the Bottom of Your Furnace Issues as Soon as Possible

Furnace problems can be an expensive headache, but not when you call Bell Mechanical Services. We’ve been providing the quality, affordable furnace repair McKinney and Frisco homeowners have relied on since {year}. Call us at 888-863-0560 to receive your free estimate today.