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 issues that are more common than others.
Let’s review these issues and about 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. 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 desired temperature is higher 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 operate 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. Because this switch resembles a light switch, it’s easy to unintentionally 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. 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 follows a specific sequence when it starts heating your home.
- Your thermostat detects the temperature has dropped and tells your furnace to turn on.
- The draft inducer fan turns on to pull in fresh air for combustion.
- The gas valve unlocks for the burners, which are ignited electronically.
- The flame sensor tells your furnace the burners have been lit.
If something is off during the sequence, your furnace will shut off as a safety precaution.
A couple of potential causes for this problem 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 getting into your home. The ignition process corrodes flame sensors over time. 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 senses backdrafting. Backdrafting is dangerous, since 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 limit airflow and cause your furnace to shut down to prevent overheating. Make sure to replace 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 tied to a wrong thermostat setting or a dusty air filter that’s limiting airflow. Use the steps above to resolve the issue.
4. Furnace Won’t Turn Off
If it’s very cold outside or you like your home to be warm, your furnace may be running 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 going even when the furnace isn’t, so it’ll sound like your furnace is running all the time.
Otherwise, 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 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
Clean Air HVAC Can Resolve Your Furnace Problems Quickly and Affordably
Furnace problems can be a costly headache, but not when you call Clean Air HVAC. We’ve been providing the quality, affordable furnace repair Pacheco homeowners have trusted since 2004. Call us at 925-233-6238 to receive your free estimate today.