Normally, your gas furnace should cycle on and off 3-8 times hourly, maintaining a comfortable temperature in your home. But a furnace that keeps shutting off every minute or two won’t heat your house properly. Not only that, it may be signalling a bigger problem that you need to take care of.
So don’t just sit there and shiver. Troubleshoot this common furnace problem and learn how to fix it.
1. Furnace Airflow Is Blocked
Your furnace’s heat exchanger needs a good flow of air to cool it down. If the airflow is obstructed, the heat exchanger will overheat, triggering the safety shutdown. That will protect your furnace but leave you in the cold. Fortunately, this is easy to resolve.
Change The Filter
Your furnace’s air filter gets clogged with dirt and dust over time, restricting airflow to the furnace. If you see your filter is blocked, all you have to do is change or clean it.
Change a disposable filter. Replacements are inexpensive and readily available, so stock on a few spares.
Clean a reusable filter. These are higher quality, but require an occasional cleaning. Vacuum off any dirt and/or gently rinse and dry the filter, according to the manufacturer’s instructions.
Going forward, check the filter monthly, and clean or change your furnace filter at least every 90 days.
Open Some Vents
You may have closed a few vents in the past when your room got too hot. That’s okay, but make sure some vents are left open. Once again, this is important to allow proper airflow to the furnace.
2. Your Thermostat Is The Culprit
Another reason your furnace keeps shutting off could be the thermostat.
Check The Setting
Ensure your thermostat is turned on and switched to “HEAT.” Also, double-check the temperature. Someone may have adjusted it to a lower setting than you’d like.
Check Thermostat Communication With The Furnace
Have a buddy stand near the furnace and listen while you adjust the thermostat from “LOW” to “HIGH.” If he or she hears a sound, the problem is probably with your furnace. If not, your thermostat is likely malfunctioning.
Check Thermostat Placement
A thermostat located in a warm spot (for example, close to the kitchen or on a sunny wall) will register a high temperature and shut the furnace off, while the rest of your room is still chilly.
Talk with us about the best thermostats and the most efficient placement. If your home tends to heat unevenly, consider a heat zoning system.
3. Flame Sensor Is Corroded Or Soot-Covered
A flame sensor problem could be why your furnace keeps shutting off. The flame sensor is a safety device designed to turn off your furnace if no flames are detected, protecting you against dangerous gas fumes. If the flame sensor becomes corroded or covered in soot, it cannot detect flames, even when your furnace is running properly. As a result, the sensor shuts the furnace down.
This is a serious issue requiring prompt professional furnace repair.
4. Furnace Is Too Big
You may have been sold a furnace which is too large for your home. If that’s the case, it will heat your rooms fast. Once the furnace reaches the set temperature, the thermostat will shut it off, causing your house to cool quickly … triggering the furnace to switch on once again. This short-cycle pattern won’t provide the home comfort you want, and is hard on your furnace, too.
Look into replacing your oversized furnace with a new, energy-efficient model that is correctly sized for your needs.
Count On Husky For Gas Furnace Repair
When your furnace breaks down on a cold Vaughan winter day, it’s a miserable experience. Fortunately, Husky is here, available to service any gas furnace make or model.
Call us 24/7 for emergency HVAC repair.
For tune-ups and non-emergency repairs: