Furnace Troubleshooting: What to Check Before Calling a Professional

First, ensure that your furnace is actually running. If your unit has a clear window, observe the sequence of LED lights. These lights often display error codes that can give you clues about the problem.

Make sure your thermostat is set to “heat” and the temperature is higher than the current room temperature. Spend about 60 seconds checking for any error messages or unusual sequences on the display.

Go to your electrical panel and find the breaker labeled for your furnace. If the breaker is tripped, reset it. If it trips again, this could indicate an electrical issue that needs professional attention.

Locate the power switch near your furnace. It could be on the ceiling, beside the unit, or even attached to the unit itself. Make sure it’s in the “on” position.

A clogged or dirty air filter can cause your furnace to shut down. Check the filter for blockages and replace it if necessary. Keeping a clean filter helps maintain proper airflow and prevents the furnace from overworking.

Turn off your furnace for about one to three minutes, then turn it back on. This simple reset can sometimes resolve minor issues.

If your furnace has a pilot light and it’s out, follow the manufacturer’s instructions to relight it. Important: If you smell gas or have trouble lighting the pilot, call a professional immediately. High-efficiency furnaces typically use a hot surface igniter instead of a pilot light, so you’ll see a glowing light during ignition if everything is working correctly.

Ensure all supply vents and return air registers are clear of obstructions. Furniture or other items blocking airflow can cause the furnace to struggle or shut down.

If your thermostat screen is blank, it might need new batteries. Open the thermostat cover (if you’re comfortable doing so) and replace the batteries if needed. Some thermostats are powered by the furnace itself, so if changing batteries doesn’t help, it’s time to call a professional.