If your furnace is blowing cold air, cycles on and off too often, or simply won't fire up, then you could have a problem with your ignition switch. Sometimes, the switch itself has a fault; other times, it won't work because of a problem somewhere else in your system.

Read on to learn about some of the common reasons why furnace ignition switches stop working.

Your Ignition Switch Has a Fault

If your ignition switch has a fault, then it can't light your furnace. For example, if the switch has cracked, has a loose connection, or has some rusted areas, then it might not spark or heat up enough to do its job and get your furnace working.

While a repair specialist might be able to repair basic damage, they may suggest that you replace the switch if it is close to the end of its working life. A repair might not last for long and a replacement might make more sense.

Your Thermostat Isn't Working

The thermostat on your furnace controls is on/off cycles. When the temperature drops lower than your thermostat level, then it triggers the ignition switch so that your furnace turns on.

Sometimes, a thermostat just has a glitch. Try turning it up to a higher temperature. This might be enough to kickstart your switch and get your furnace working again.

If this doesn't work, or if the problem returns when you turn the thermostat back down to its regular setting, then you could have a thermostat fault. Once you fix it, your furnace should ignite normally again.

Your Gas Valve Has a Fault

If your furnace's gas valve stops working, then your ignition switch won't work either. You might hear the switch click, but your furnace won't actually produce any heat.

Sometimes, a valve breaks, gets stuck, or becomes unstable. Instead of opening to feed gas to the switch's ignition, no gas comes out. You need to have your line and supply checked to find the problem.

Your Burners Are Clogged

The burners in your system keep it working during a cycle. They burn the gas that heats your home.

However, burners can get clogged up and blocked by dirt and debris. When this happens, they might not burn hot enough. Your system might shut down your ignition switch for safety reasons. Once you clean the burners, your switch should start working again.

To find out exactly what is wrong with your switch, contact furnace repair professionals near you.