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The First Things to Check If Your Furnace Won’t Turn On

family of three huddled together on couch for warmth

The weather outside is frightful, and now your furnace is feeling spiteful! Is it time to call a technician? Not quite. Fortunately for many homeowners, a lot of furnace issues can be solved by going through a quick checklist of troubleshooting steps—no technician necessary.

If your heater won’t turn on, or if it started to run then stopped abruptly, here are the first things you should check.

1. The Thermostat

You should always check your thermostat to see if it’s even responding. If the screen is unresponsive or acting strangely, the thermostat may need new batteries. Also, make sure that your thermostat is set to heat your home (rather than cool) and that it’s switched to “auto,” instead of “on.”

2. Your Circuit Breaker Panel (or Fuse Box)

Your furnace is a high-powered piece of equipment, and sometimes excess electrical current can cause it to trip a circuit breaker switch (or blow a fuse, if you own an older electrical panel).

3. The Furnace Door

In many newer furnace models, the equipment won’t run unless the furnace door snaps firmly in place. Just to be sure, try opening the unit’s door and closing it again.

4. The Air Filter

When your system’s air filter becomes clogged with dust, dirt, and hair, it will block airflow into your furnace. Lack of airflow is the number one reason why heating equipment overheats. Some systems automatically shut down when overheating starts to occur, preventing extensive damage to the furnace.

If your furnace starts to run, only to shut down or short cycle, it’s a good bet that the air filter is too dirty. Put in a clean replacement to see if that solves the issue.

5. The Furnace’s Power Switch

Your furnace has an ON/OFF switch. In some cases, a technician or family member may have turned this switch off. Look for the switch either on your furnace or on the wall beside it. It should look like an ordinary light switch.

6. The Furnace’s Gas Supply (If You Own a Gas Furnace)

Without fuel, your gas furnace will have nothing to convert into heat. Look for the gas pipe leading into your furnace, and locate the little knob or lever located on the line. That device is the valve that controls the flower of gas to your furnace.

By turning the lever perpendicular to the gas line, you’ll stop the flow of gas. By turning the level parallel to the gas line, you’ll allow gas to flow to your furnace.

Still having trouble with your furnace? Our Milford heating technicians are ready to help! Schedule your furnace repair with Tri-City Heating and Cooling today by calling (203) 303-5700.