Short Cycling Gas Furnace Repair That You Need To Know

Furnaces, like any other machines and household appliances that we have, are also prone to common wear and tear as well as part or system malfunction. One common furnace issue that must be dealt with immediately is short cycling or overactive.

What is Short Cycling?

Short cycling happens when your furnace does short bursts of activity and intermittently turns on and off every few seconds, normally between four to seven seconds. Furnace start-up is the most strenuous part in a furnace’s operation, and for your furnace to do it over and over again makes it harder for the system to endure leading to parts and eventually a system breakdown.

If left unchecked, it can cause serious and long-term damage to your overall heating system that may cause even more trouble and money for repairs.

Importance of Fixing Short Cycling

Hinder Increase Energy Use

Furnaces use more energy when starting up than when it is already running. So when it keeps turning on nonstop, a whole lot of energy is wasted for unnecessary startups. This leads to lower energy efficiency and higher energy consumption, hence, a hike in electricity bills.

Maintain Safety At Home

A furnace that short cycles may be a mere effect of a bigger and more serious problem. Some of which, if ignored, can pose a great threat to your home and family’s safety.

Maintain Comfort

If your furnace keeps on turning on and off, it will result with indoor home temperature to be too hot or too cold which can be really annoying and uncomfortable. If the unsteady temperature persists, it can even affect your family’s health and promote poor sleep.

Prevent System Breakdown

Prolonging furnace short cycling will cause you more parts of your furnace to collapse because of the extra strain experienced during multiple start ups. This will eventually lead to a bigger problem which is your entire furnace breaking down. So instead of just a minor malfunction which can be easily fixed, now you’ll deal with an expensive repair or worse, a system replacement.

Common Causes of Furnace Short-Cycling

Dirty, Rusted or Faulty Flame Sensor

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A very common sign of a flame sensor problem is a short cycling furnace. This happens because a dirty, rusted or faulty flame sensor won’t be able to sense the presence of heat and will command your furnace to shut down every time you turn it on.

Most often than not, if your flame sensor experiences problems, it is not broken, but just dirty. Check out this blog for a complete guide on how to clean your furnace flame sensor.

Should you be facing a damaged flame sensor, here is a helpful blog for you: Flame Sensors Repair & Replacement: All You Need To Know.

Thermostat Issues

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There are a couple of probable reasons for your thermostat to cause your furnace to short cycle. One is when it is placed in a wrong position inside your home. If your thermostat is placed near a heat source or in direct sunlight, it can sense heat all too quickly and may signal your furnace to shut down even though the correct indoor temperature is not yet achieved.

Also, failing to program your thermostat to heat mode can cause your furnace to short cycle. Before making an assumption, that your thermostat might be broken, first make sure that it is in the “heat” function.

Finally, your thermostat may really be damaged. A broken thermostat may signal your furnace to switch on and off regardless of the indoor temperature. To rule this out, set the heat anticipator level on your thermostat one calibration mark closer to the “longer” setting. Give it some time, but if you notice that the short cycles persist, it is best for a professional to check your thermostat wiring or have your thermostat replaced.

Replacing the thermostat will usually solve the issue. Choose among our long list of high-quality thermostats for great comfort, ease and efficiency.

Clogged or Dirty Air Filters

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A dirty or clogged furnace filter restricts system airflow so warm air that should be vented out to warm your home are retained inside your furnace. This makes your furnace’s temperature to rise up and causes it to shut off. And since your home is not warm enough yet, it triggers your thermostat to turn on the furnace for another cycle.

Fortunately, cleaning and replacing your furnace air filters is easy and can be done by yourself at home. Simply slide the old filter out of the filter cabinet, take note of the direction of the arrows in the filters (your new filters must be positioned in the same way), and note the filters dimension.

Purchase your new furnace filters at ACEHVACPARTS and install it noting the printed arrows direction.

System Overheating

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Another common reason for a short cycling furnace is constant system overheating. This can be caused by your furnace’s temperature-monitoring devices to be faulty. Usual built-in furnace components that monitor temperature to look into are the limit switch and the heat exchanger. A damaged or cracked heat exchanger, for example, can release heat inside your furnace which can cause overheating and frequent short cycling.

Oversized Furnace

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Oversized furnaces in a small home will deliver heat in all rooms more quickly but unevenly. This will lead the furnace to short cycle as it tries to achieve a consistent indoor temperature in various rooms throughout your home.

If you’re still experiencing uneven temperature between rooms after your furnace short-cycle issue is fixed, then you might have an unbalanced duct, check this blog Duct Airflow Balancing Tips And Guide You Need To Know to help you out.

Moreover, poor insulation in a house with an oversized furnace can also cause frequent on and off cycle. Because most of the heat produced by furnaces are lost through cracks, holes, or faulty seals, it causes the furnace to short cycle to keep up with the missing heat and maintain a constant temperature.

Should you need new HVAC replacement parts, accessories, and supplies while fixing your furnace’s short-cycle issues, check out and use this coupon code IQK5657F6I to get $5.00 off your order total!

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