Why Is My Furnace Not Working?
When the temperature outside dips, it's more important than ever that you keep the temperature inside your home stable and comfortable for your family. But when you go to turn up the heat and nothing happens, it can make you panic.
Here are some common reasons your furnace may not be working, and what you can do to fix it quickly.
Thermostat
Your "furnace problem" may not actually be an issue with your furnace — it could be a problem with your thermostat. Here are some things to check to see if your heating issue lies in your thermostat:
Make sure it's set to "Heat" instead of "Cool" or "Off."
Check the temperature setting.
Set the thermostat temperature five degrees higher than the room temperature to see if the furnace turns on.
If you have a programmable thermostat with set routines, check that the thermostat is displaying the correct day and time.
Check the thermostat wires to see if there are any breaks, especially if you've recently remodeled.
Replace the battery.
Open the thermostat and gently blow out any dust or debris. Check that it's level, firmly attached to the wall and that none of the wires are loose.
Breaker
A power surge or loss of power could be the cause of your furnace not working. Check your circuit breaker to ensure that one of the switches isn't flipped. Also check for a wall switch near the furnace and that it's switched to "On."
Supply
If your furnace runs on propane or LP gas, check to see that you still have plenty of fuel in your tank. Most propane systems will continue to work until they're nearly empty, but some will sputter and not supply enough gas to fire your furnace when it's getting close to empty.
For those who are on a city gas line, you will need to call an HVAC technician if you suspect you've got gas supply issues.
Air Filter
When your furnace's air filter is getting clogged up, it will cause your furnace to turn off. A clogged filter means the air can't flow properly, which will not produce the required mixture of gas and air that allows your furnace to ignite.
Check your furnace's air filter to see if it's clogged by dust and debris. Change it out for a new one and see if that helps your problem.
As a good rule of thumb, plan to switch out your air filter at least once every three months, or more frequently if you have a lot of people living in your house or you have pets.
Learn more: 6 Furnace Maintenance Tips for Fall
Ignition
There are two ways furnaces ignite: pilot lights and electric ignition switches.
If you have a pilot light, check the bottom of your furnace to see that the pilot light is lit. In the event that it isn't lit, you can try using a long match or lighter to carefully relight the pilot light.
For electronic igniter switches, you'll also look in the bottom of the furnace. See if the igniter glows when your furnace tries to start up and you hear a clicking noise. Repeated clicking in short intervals means your igniter isn't coming on to ignite your furnace.
You can try reaching in and gently cleaning the igniter and area around it, but be very careful since the igniter tip is fragile. This can rid it of built-up carbon that prevents the igniter from working. If you do this, be sure to turn your furnace off first!
Draft Issues
Your furnace has a motor called a draft motor or draft inducer motor. This creates the humming noise you hear when your thermostat first sends the signal to start the furnace and before you hear the "whoosh" of the burners starting up.
This motor could be blocked by a bird or raccoon nest or even heavy snow and ice. If you hear the motor hum but the furnace doesn't ignite, this could be the cause of your problem. Clear the obstruction and see if the furnace kicks on after that.
However, your draft motor could also just stop working. In this case, the motor won't come on at all and you will need to call an HVAC technician for a furnace repair call.
Limit Switch
The limit switch, also called the high limit switch, is designed to shut down your furnace if it gets too hot, such as when the air filter is clogged and hot air builds up and can't be circulated. While you could DIY this, it's usually best to call a professional HVAC company to come out for a quick service call and check the limit switch and determine the cause behind it being open.
Your Trusted HVAC Repair Team in Raleigh
Whether you need a routine maintenance call, have an emergency furnace issue or you're looking to replace your HVAC system, the team at Heating + Air Paramedics of Raleigh can help. We carefully assess your problem and make only necessary recommendations — we'll never upsell you on something you don't need. Call today!
