Furnace Starts Then Stops

Dec 29, 2020

What’s more blissful than warm air on a cold day?

You’re relaxing in your cozy home, kicking your feet up by the air vents and pretending that you’re beside a fireplace. You don’t have a care in the world—that is, until you hear your furnace go silent just minutes after starting up. Suddenly, your fireplace fantasy comes to a halt.

What gives?

In previous blogs, we’ve talked about how your air conditioner can short cycle. As it turns out, the same thing can happen with your furnace. The average heating cycle is 10-15 minutes; if yours is much shorter, you’ve got a problem on your hands.

Curious about what’s got your furnace acting up? We’ve got a list of the most common problems that make your heating system stop and start:

The Airflow Is Restricted

The airflow of your furnace can be blocked by all sorts of things. For one, the vents themselves might be obstructed by debris. Another problem could also be caused by the filter in your furnace; either it needs to be replaced with a fresh one, or the filter material may be too restrictive for your system. It’s important to check the manufacturer’s label on your furnace to see what kind of filters are best for your system.

The Flame Sensor Is Defective

Your burner is powered by a flame to produce heat. Since your furnace doesn’t have eyes, it uses the flame sensor to detect if the flame is burning. This is an important safety measure since it’s linked to the gas valve, which powers the flame. Basically, if your flame sensor doesn’t detect fire, it shuts off the gas valve. Your heating cycle will end abruptly as a result.

The Draft Inducer Motor Is Faulty

This component is what feeds oxygen to the burner and prevents gases from polluting your indoor air. Without it, your furnace wouldn’t be very useful at all—it’d be downright dangerous.

When the draft inducer motor doesn’t do its job, you end up with a short cycling furnace. This is because it also controls the pressure switch, another component that starts the ignition process. A motor that can’t turn off the pressure switch delays the ignition process; after a while, your furnace will shut off entirely. To remedy this issue, you may need to replace your draft inducer motor.

The Pressure Switch Is Failing

What if your draft inducer motor is perfectly functional, but your furnace still won’t work? It may be related to the pressure switch. This is a signal that tells your furnace, the airflow is good, so keep the ignition going! It can detect whether the combustion gases are being sent outside or recirculating through the home, making it an important safety measure. But if the pressure switch fails, it won’t be able to close, and this will delay the ignition process. It’s important to replace a faulty pressure switch to keep your furnace functional and your air gas-free.

There’s a lot that can go wrong with your furnace—these fixes aren’t meant for a DIY repair. Contact Provincial Heating & Cooling for all your Winnipeg furnace maintenance. We’ll look after these issues ASAP so you can escape from Winnipeg’s winter cold. As it get hotter see our AC repair services.


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