Why Does Your Furnace Turns Off and On

Most of us experience furnace problems, especially during cold stretches. Many of us wonder why our furnace turns off and on repeatedly, aka short cycling. Short cycling, though, is confused by many people.

How Can I Tell If My Furnace is Short Cycling?

It is straightforward to tell whether your furnace is short cycling as it will repeatedly turn on and off in a short duration of time. It can shut off and on for about two seconds to two minutes.

In contrast, A typical furnace switches on and off a few times every hour often lasting five minutes or longer. It is effortless for the furnace to reach the home’s desired temperature.

The amount of time it takes for a house to reach the desired temperature depends on many factors, including the home’s size, the outside temperature, the insulation, and the furnace type. For instance, suppose you have an older home with poorly insulated windows.  In that case, the furnace will overwork itself to maintain the temperature back at home.

Related: Why won’t my furnace turn on?

Causes of Short Cycling in a Furnace

Below are some reasons why your furnace turns off and on repeatedly and how to avoid such furnace problems.

Overheating furnace

Depending on whether your furnace is new or old, it affects the performance of the furnace. Older furnaces overheat more as opposed to newer furnaces.

When airflow is restricted, furnaces overheat. Overusing your furnace can cause some of the furnace components to wear out quickly, leading to frequent repairs.

Suppose your furnace back at home is overheating. In that case, you should check and maintain the furnace filters. The filters are supposed to be clean, as well as the furnace itself. Dirt and debris accumulate in your furnace, which restricts airflow, thus making it very difficult for the furnace to carry out proper air circulation.

If the air filters in your furnace are dirty, you should replace them or upgrade them to improve air quality indoors.

Flame sensor

A faulty flame sensor is a common cause of short cycling in furnaces. The furnace flame sensor gauges the amount of gas reaching your furnace.

When the flame sensor accumulates dirt over some time, it will not have the ability to determine the right amount of gas reaching the furnace. It can even mess up with the safety features, including the gas valve, which is supposed to cut off the gas supply to prevent excessive gas buildup.

You should regularly clean your flame sensor and schedule a complete furnace tune-up.

The blower motor in the furnace is not working

A furnace can function when the blower motor is off. However, if the blower motor is not working, short cycling could be the result.

The blower motor in your furnace is responsible for blowing air over your heat exchanger to undergo heating. Suppose the blower motor in your furnace has ceased functioning. In that case, much heat will build up in your furnace, thus triggering some of the furnace’s safety features that include the high limit furnace switch.

You should regularly check and ensure that the blower motor in your furnace functions correctly. You should also check your vent system. When you put on the furnace back at home, you should check if any air arises from the vents. If there is no air coming from the vents, then this could be the issue.

A wrong size furnace in your home

A wrong-sized furnace is a significant issue of concern when you replace the home furnace. It begins to shut off and on repeatedly. An oversized type of furnace will use much energy. Hence it will switch on and off more often because the furnace warms up your place quickly.

When the furnace has quickly warmed up your house, it will switch off. When the inside temperature drops, the furnace turns back on. The cycle continues, which in turn overuses your furnace.

The thermostat is not working properly

In some cases, you can find that thermostats similar to the other devices around your house can easily malfunction when not correctly maintained. In case your residential thermostat is not working correctly. It is giving out false readings; this will, in turn, cause your furnace to shut off and on repeatedly.

Check the thermostat batteries to ensure they are correctly charged. In addition, adjust the thermostat to the desired temperature.

Regularly Maintain Your Furnace

You are already aware of the different reasons why your heating system turns off and on repeatedly as it is not supposed to and how you can deal with the situation. Regular cleaning and maintenance of the furnace are mandatory in ensuring that your furnace has excellent performance and a long lifespan.

Suppose you are unsure how to fix specific furnace problems. In that case, you should be in an excellent position to schedule a call with your trusted HVAC technician to solve the furnace problem on your behalf.