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 typical than others.
Let’s review these problems and about what they might cost to fix so you know before you contact an HVAC technician. Some of the most common furnace repair issues 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 few 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 preferred temperature is greater 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 run 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 located on or close to it. Because this switch resembles a light switch, it’s easy to unintentionally turn it off. If it was off, it may take your furnace a few minutes to start.
- Is the air filter clean? A dusty 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 problem can be complicated, so the estimated cost to repair it depends on what’s wrong.
2. Furnace Won’t Stay Lit
Your furnace uses a specific sequence when it begins heating your home.
- Your thermostat detects the temperature has fallen and tells your furnace to start running.
- The draft inducer fan turns on to pull in fresh air for combustion.
- The gas valve unlocks for the burners, which are lit electronically.
- The flame sensor signals to your furnace the burners have been lit.
If something is wrong during the sequence, your furnace will shut off as a safety precaution.
A couple of potential 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 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 ultimately 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 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 operate.
- Dirty air filter. A dirty air filter can reduce airflow and cause your furnace to shut down to avoid overheating. Make sure to change yours every 30 to 90 days, or anytime you can’t see light through it.
Estimated Repair Cost
These costs are estimates, so it’s important 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. Furnace Won’t Blow Hot Air
In many cases, this problem is linked to a wrong thermostat setting or a dirty air filter that’s limiting airflow. Use the steps above to fix the issue.
4. Furnace Won’t Turn Off
If it’s very cold 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, make sure your thermostat is set correctly and working properly. If your fan setting is at “on,” the blower motor will be going even when the furnace isn’t, so it’ll sound like your furnace is running all the time.
Alternatively, there might be a problem with the blower motor or your ductwork may be losing air, forcing your furnace to run constantly to make up for the air loss.
Estimated Repair Cost
These costs are estimates, so it’s necessary 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
Olde Towne Heating & Air Can Solve Your Furnace Problems Quickly and Affordably
Furnace problems can be an expensive headache, but not when you work with Olde Towne Heating & Air. We’ve been providing the quality, affordable furnace repair Mount Pleasant homeowners have trusted since 2009. Contact us at 843-485-0967 to request your free estimate today.