Your furnace is a key part of your home. Without one, you wouldn’t be able to keep warm during the winter. Yet furnaces can have some issues that are more typical 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 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 couple of reasons why your furnace won’t turn on, so make sure to check all of them.
- Is your thermostat set correctly? Make sure it’s set to “heat,” “auto” and that your desired temperature is greater than the room’s current temperature. If you use 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 found on or near it. Because this switch looks like 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 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 complicated, 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 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 opens 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 off as a preventive measure.
A couple of possible causes for this problem include:
- Dirty or malfunctioning flame sensor. If the sensor doesn’t sense a flame, it will shut 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 replaced.
- 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 fail due to age, damage or dust accumulation.
- 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 limit airflow and force your furnace to shut off 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 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 tied to an incorrect thermostat setting or a dusty air filter that’s limiting airflow. Follow the steps above to resolve the problem.
4. Furnace Won’t Turn Off
If it’s very chilly outside or you like your home to be warm, 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 going 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 continuously to make up for the lost air.
Estimated Repair Cost
These costs are approximations, so it’s important to note yours may be different based on your furnace’s brand and model.
- New blower motor: $250–$800
- Seal ductwork: varies based on house size
Giordanos Heating and Air Conditioning Can Solve Your Furnace Problems Quickly and Affordably
Furnace problems can be an expensive headache, but not when you call Giordanos Heating and Air Conditioning. We’ve been delivering the quality, affordable furnace repair Derby homeowners have relied on since 1979. Call us at 203-772-8319 to receive your free estimate today.