Your furnace is a key part of your home. Without one, you wouldn’t be able to stay warm during the winter. Yet furnaces can have some issues that are more typical than others.

Let’s go over these issues and discuss what they might cost to fix so you know before you contact an HVAC technician. Some of the most common furnace repair problems involve:

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

1. My Furnace Can’t Start

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

  • Is your thermostat set correctly? Make sure it’s set to “heat,” “auto” and that your desired temperature is higher than the room’s current temperature. If you use a programmable thermostat, make sure it has fresh 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 close to it. Because this switch resembles a light switch, it’s easy to accidentally turn it off. If it was off, it might take your furnace a few minutes to start.
  • Is the air filter clean? A dirty air filter can cause 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 uses a certain sequence when it begins heating your home.

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

If something is off during the sequence, your furnace will shut down as a safety precaution.

A couple of possible causes for this issue include:

  • Dirty or malfunctioning flame sensor. If the sensor doesn’t detect a flame, it will turn off your furnace to prevent natural gas from spilling into your home. The ignition process corrodes flame sensors as time passes. While cleaning during annual furnace maintenance can help, yours may eventually need to be taken out and changed.
  • Bad limit switch. This safety feature will shut off your furnace if it detects backdrafting. Backdrafting is dangerous, because carbon monoxide and natural gas can leak into your home. These switches can malfunction due to age, damage or dust accumulation.
  • 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 reduce airflow and cause your furnace to shut off to prevent overheating. Make sure to change 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 important to note yours may vary 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 Won’t Blow Hot Air

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

4. The Furnace Isn’t Shutting Off

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

If this isn’t the case, make sure your thermostat is set correctly and running 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 running 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 constantly to make up for the air loss.

Estimated Repair Cost

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

  • New blower motor: $250–$800
  • Seal ductwork: varies based on square footage

Custom Air Systems Inc Will Work Hard to Resolve Your Furnace Issues Quickly and Affordably

Furnace issues can be an expensive headache, but not when you work with Custom Air Systems Inc. We’ve been providing the quality, affordable furnace repair Port St. Lucie homeowners have relied on since year. Call us at 772-247-2283 to request your free estimate today.