It’s a chilly day, and all of a sudden, your house isn’t getting warm the way it should. You fiddle with the thermostat, turn it up and wait and … nothing. If your furnace isn’t on, you’re not the only one. This problem is experienced by many homeowners, particularly during the cold seasons. But before you jump to worst-case scenarios, it’s worth exploring the many potential issues that could cause it.

The thermostat is one of the most frequent causes when a furnace is not working. If it’s not set to heat or the batteries are dead, it will just ignore the thermostat entirely. That and make sure it’s on the right setting — and maybe even replace the batteries — before jumping to any conclusions.

Then check the circuit breaker, as your heating system may have lost power due to a tripped switch. Your heating system may have lost power if you tripped a breaker. If the breaker that powers the furnace trips, simply resetting it may be all that’s needed to get the system back up and running.

The air filter system is another place you want to look at. Air that can’t move through will cause the furnace to overheat and shut down (for safety). Cleaning the filter seems like an easy way to fix a problem such as dirty water, but it can easily be forgotten, and just as easily replenish the diatom filter.

If your furnace still does not turn on, check the pilot light or ignition system, depending on your furnace type. Failure of the ignition can also prevent your furnace from generating heat, of course, even if everything else seems to be running just fine. Gas heaters may have a bad thermocouple or gas valve that needs wiping out or replacing by a pro.

Also, check the blower motor or limit switch. If the blower motor is shot or the safety limit switch is no longer working, the furnace may not blow out warm air via the ducts.

A furnace not working isn’t always a cause for panic. However, disregarding the matter can result in more expensive damage and prolonged discomfort. Regular maintenance, such as annual checkups and tune-ups, can keep problems at bay early on and add years to your system’s life.

In some situations, when you’ve looked under every stone, you’re still going to have to summon a licensed HVAC professional. More complicated electrical issues, gas line issues, or just worn-out parts are all best left to a professional who can safely troubleshoot and make repairs to your unit.

After all, a furnace that isn’t working doesn’t have to signal the end of the world — it just means there’s some work to be done to figure out the problem and to get help, as needed, to warm things up again.

David Williams is author of the article. For more details about annual furnace maintenance please visit our website: airzonehvac.ca