Why did my furnace stop working? This is a question we get often, especially when the colder months come around. The last thing you need is for your furnace to shut off on a cold day and you can’t get it back on. It is frustrating and stressful, especially when you don’t know what is causing it. It can even be dangerous. So here are six of the most common reasons why your furnace may be blowing cold air. Some of these you can easily fix, while other’s will require the help of an expert.

1. Thermostat

Have you checked the thermostat? It might sound silly, but sometimes the reason your vents are blowing cold air is because your thermostat is telling them to. It is possible that a member of your household bumped the switched or pressed a few buttons switching it to cool or fan only. A quick and easy fix.

2. Closed Vents

Another simple solution if one or two rooms are not heating up, it might be because a vent was shut accidentally. Or the vents might be shut to regulate air flow. Simply open the vents and notice the difference right away. As a note, most HVAC professionals don’t recommend you close vents to regulate air flow. It can cause issues with the way your system operates and decrease efficiency.

3. Electrical Issue

If your furnace has shut down completely it could be a tripped circuit breaker. Before you call over a technician, switch the breaker to see if that corrects the problem. If not, then by all means give us a call. It could be an internal electrical problem that a professional heating technician should address.

4. Pilot Light

More modern furnaces don’t need the pilot light on all the time. However, if your furnace is older it may have blown out. Check that first and see if you can get it to come back on. Most furnaces will have instructions on how to do this printed right on the front of the system.

5. Gas Valve

For the pilot light to stay on and for your furnace to work, the gas valve needs to be open to fuel your system. It is a simple check. If the handle of the valve is perpendicular it means your pipe is closed. If it lines up with the pipe, the valve is open. Just double check to make sure your furnace is getting gas.

6. Overheating

What typically happens is your furnace starts out blowing warm air, but then switches to cold before it shuts down. What causes this problem? Usually a clogged furnace filter. Because it blocks airflow the furnace has to work harder and longer to heat your home until it simply overheats. Some furnaces have a limit switch. This safety device switches over when your furnace overheats. It turns the burners off, but keeps the fans blowing to help cool the furnace back down. Unfortunately repeated overheating can ruin the heat exchanger. Try changing the filter to see if your furnace starts working consistently again.

7. Broken Heating Element

Aside from these simple fixes, there may be a larger issue inside the furnace. These problems are more difficult to solve. Only a trained heating professional should address a broken heating element or igniter. This is not only a more complex problem, but is for your own safety.

Have an issue with your furnace service San Jose, CA and not sure what to do? Call the professionals at Pelle Heating & Air Conditioning. Our family owned and operated company has been serving the Bay Area since 2002. You can reach us at (408) 800-2791. Or come by 1045 N 10th St San Jose, CA 95112 for more information about our maintenance and repair services.