Your furnace is an integral part of your home. Without one, you wouldn’t be able to stay warm during the winter. Yet furnaces can have some problems that are more typical than others.
Let’s review these problems and about what they might cost to fix 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. Furnace Won’t Turn 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 correctly? Make sure it’s on “heat,” “auto” and that your preferred temperature is greater than the room’s current temperature. If you have a programmable thermostat, make sure it has new 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 near it. Since 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 turn on.
- Is the air filter clean? A dusty 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. Furnace Won’t Stay Lit
Your furnace follows a specific sequence when it starts heating your home.
- Your thermostat notices the temperature has dropped and tells your furnace to start running.
- The draft inducer fan turns on to bring in fresh air for combustion.
- The gas valve unlocks for the burners, which are ignited electronically.
- 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 sense a flame, it will turn off your furnace to prevent natural gas from spilling 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 taken out and changed.
- Bad limit switch. This safety feature will shut 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 operate.
- Dirty air filter. A dirty air filter can limit airflow and force your furnace to shut down 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. 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 restricting airflow. Use the steps above to fix the problem.
4. Furnace Won’t Turn Off
If it’s very 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 running 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 on all the time.
Alternatively, there might be a problem with the blower motor or your ductwork may be losing air, making your furnace run continuously to make up for the lost air.
Estimated Repair Cost
These costs are approximations, 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
Stieferman Heating Company Inc Can Resolve Your Furnace Issues Quickly and Affordably
Furnace problems can be an expensive headache, but not when you work with Stieferman Heating Company Inc. We’ve been providing the quality, affordable furnace repair Jefferson City homeowners have relied on since 1956. Contact us at 573-203-3908 to request your free estimate today.