Why Won’t My Furnace Turn On?
January 29, 2018

With the cold winters in the New Holland area, a malfunctioning furnace can be a major health and safety concern, as well as a significant inconvenience. Many things can cause startup problems in a typical furnace, from the wrong thermostat settings to a blower motor that has failed. Although most furnace problems should be handled by a professional, there are a few things that you can check yourself before calling an HVAC service.

A person is adjusting a thermostat on a wall.

Common Furnace Startup Problems and Solutions

Sometimes, minor problems can prevent a furnace from turning on, and with a bit of troubleshooting, you may be able to avoid the expense and inconvenience of a service call. Some of the most common causes of furnace startup problems include:

Tripped Breakers

Occasionally, high loads can cause the breakers for a furnace to trip, even if the system is in otherwise good condition. Reset the breakers by turning them off, then back on. If the breakers trip frequently, it may be a sign of a more serious problem, and you should have the furnace inspected as soon as possible. Some furnaces may also have their own power switch, located near the furnace or mounted on the furnace itself. Make sure that switch is turned on.

Incorrect Thermostat Settings

It the settings on the thermostat are accidentally changed, or the batteries are low on programmable models, the furnace may fail to operate. Make sure the thermostat has fresh batteries, and that it is set to the appropriate temperature and mode.

Clogged Air Filter

Some furnaces may shut down if the air filter is clogged to prevent overheating and system damage. If your furnace fails to start, make sure the air filter is not dirty or clogged, and replace it if necessary.

Clogged Condensate Drain

High-efficiency, condensing gas furnaces generate moisture from the flue gases as they operate. If this moisture has nowhere to go due to a clogged condensate drain, a float switch may shut the furnace off. If you can reach the condensate drain, remove any debris and carefully clean it using a vacuum, compressed air, or a thin wire.

Pilot Light Problems

As a safety feature, furnaces shut off if they detect that the burners are not lit, to avoid fires, form an accumulation of gas or propane. In older systems, a constantly-burning flame called a pilot light is used to ignite the burners as required. A thermocouple senses the flame of the pilot light, and if it goes out, the gas supply is extinguished. If your furnace will not start, make sure the pilot light is operating, and relight it if necessary. Also, make sure the thermocouple is close enough to sense the flame.

Electronic Ignition Problems

In newer furnaces, the burners are lit by an electronic igniter that operates only when necessary. A flame sensor is used to verify that the burners have been lit, and if it cannot, the gas supply is shut off. A dirty sensor may not be able to detect the flames, and if your furnace will not start, the sensor may simply need to be cleaned.

Furnace Repair Services in New Holland, PA

If you cannot locate the cause of your startup problems, you may need professional assistance. Our team at The Witmer Company can help. Our certified HVAC experts can diagnose and repair most furnace problems quickly, and we also feature available 24-hour emergency services for help at any time, day or night.

For furnace repairs in the New Holland area , contact us today at 717-288-7163!

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