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Why Won’t My Furnace Ignite?

We’re going through an unusually warm spell for February, but it’s sure to get cold again before winter ends. When the temperature drops outside, the last thing you need is for the furnace to stop working.

Before you call a professional for heating repair service, consider these possible reasons why your furnace won’t turn on:

1. The Furnace Needs Power

The first step is to make sure the heater is receiving electrical power. Even if you have a gas furnace, electrical igniters and other inputs need electricity to work. Check the circuit breaker box and reset any that have tripped. Then, check next to the furnace for a switch and flip it on.

2. The Thermostat Is Set Incorrectly

If a power failure interrupts a programmable thermostat’s settings, it may reset to default. Make sure the thermostat has power, is turned on, and set to “heat” mode. Turn the temperature up and see if the furnace ignites.

Technician checking a customer's thermostat settings after completing furnace repair.

3. The Pilot Light Has Gone Out

While many heaters today start with an electronic ignition, yours may have a pilot light. As a safety feature, your furnace won’t light if the pilot is out. It’s relatively easy to relight this on your own, but if you don’t feel comfortable, call a heating technician for help.

4. The Condensate Pan Is Full

Modern high-efficiency furnaces are called condensing furnaces because they produce mildly acidic condensation when they operate. If the condensate drain is clogged, the collection reservoir can fill with liquid, activating the float switch and shutting off the furnace to prevent water damage. Check the condensate pan, empty it, and unclog the drain if you can.

5. The Air Filter Is Clogged

If the furnace was just running, but now it won’t turn back on, a clogged filter may have caused it to overheat. Check the filter, replace it if it appears dirty, and try running the furnace again in a few minutes.

6. The Gas Supply Is Shut Off

Gas furnaces need a steady flow of fuel to ignite. Check the gas shut-off valve and make sure it’s in the open position. Check other gas-fired appliances around your home, such as the stove or water heater, and see if they’re working. If not, it looks like you’ve found the problem, and it’s time to call the gas company.

Choose Arctic Air Conditioning: Schedule Furnace Repair in Central New Jersey

If your furnace won’t light even after attempting these troubleshooting tips, schedule a furnace repair without delay.

For service in Monmouth, Middlesex, Mercer, or Ocean County, contact Arctic Air Conditioning today.

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