Your furnace is a key part of your home. Without one, you wouldn’t be able to stay warm during cold weather. Yet furnaces can have some problems that are more typical than others.
Let’s review these problems and about what they might cost to correct 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. Furnace Won’t Turn On
There are a couple of reasons why your furnace won’t turn on, so make sure to check all of them.
- Is your thermostat set right? Make sure it’s on “heat,” “auto” and that your desired temperature is greater than the room’s current temperature. If you have a programmable thermostat, make sure it has fresh batteries.
- Is the circuit breaker tripped? Your furnace can’t run if it doesn’t have electricity. Reset the switch if it’s facing the outside of the electrical panel.
- Is the furnace switch off? Your furnace has a power switch located on or near it. Since this switch looks like a light switch, it’s easy to unintentionally turn it off. If it was off, it may take your furnace a few minutes to turn on.
- Is the air filter clean? A dirty air filter can create a lot of issues for your furnace. Replace yours if you can’t see light through it.
Estimated Repair Cost
This issue can be complex, so the estimated cost to repair it depends on what’s wrong.
2. Furnace Won’t Stay Lit
Your furnace uses a certain sequence when it starts heating your home.
- Your thermostat notices the temperature has fallen and tells your furnace to turn on.
- The draft inducer fan turns on to bring in fresh air for combustion.
- The gas valve opens for the burners, which are ignited electronically.
- The flame sensor tells your furnace the burners have been ignited.
If something is wrong during the sequence, your furnace will shut off as a preventive measure.
A couple of possible causes for this issue include:
- Dirty or malfunctioning flame sensor. If the sensor doesn’t detect a flame, it will shut off your furnace to keep natural gas from getting 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 replaced.
- Bad limit switch. This safety feature will turn off your furnace if it senses backdrafting. Backdrafting is hazardous, because carbon monoxide and natural gas can leak into your home. These switches can fail due to age, damage or dust buildup.
- Old thermostat. If your thermostat isn’t working properly, your furnace won’t be able to run.
- Dirty air filter. A dirty air filter can restrict airflow and cause your furnace to shut off to avoid 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 necessary 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. Furnace Won’t Blow Hot Air
In many instances, this problem is linked to an incorrect thermostat setting or a dusty air filter that’s limiting airflow. Use the steps above to fix the problem.
4. Furnace Won’t Turn Off
If it’s extremely chilly outside or you like your home to be toasty, your furnace may be working for a long time.
If this isn’t what's happening, ensure 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.
Otherwise, 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 house size
Northern Comfort Inc Can Solve Your Furnace Problems Quickly and Affordably
Furnace problems can be an expensive headache, but not when you call Northern Comfort Inc. We’ve been providing the quality, affordable furnace repair Mankato area homeowners have trusted since 1975. Contact us at 507-387-6596 to request your free estimate today.