Why Is My Electric Furnace Short Cycling?

Short cycling may be caused by a blocked or filthy air filter. Your system’s airflow might be suffocated by a blocked or filthy air filter. Reduced airflow might create brief cycling symptoms as well as putting pressure on your system. Check the temperature on your thermostat.

Similarly, How do I stop my furnace from short cycling?

The most prevalent reason of short-cycling is a filthy air filter. If your air filter is blocked with dirt, air passage to the heat exchanger will be restricted. This may cause the furnace to overheat, forcing the high limit switch to intervene and turn off the heater.

Also, it is asked, What causes a electric heater to short cycle?

The thermostat is incorrectly calibrated and displays inaccurate temps. This will force the heater to shut off before it is required. The interior coil of a heat pump may have iced over. This reduces heat absorption and causes issues such as short-cycling.

Secondly, How often should an electric furnace cycle?

3 to 8 times an hour

Also, Can a bad thermostat cause a furnace to short cycle?

Short cycling may be caused by thermostat issues. Because turning on and off your furnace or central air conditioner consumes a lot of energy, you should let it run for at least 15 minutes before turning it off.

People also ask, Why does my furnace come on for a few seconds?

Your thermostat may be defective or damaged if your furnace keeps going off and on too rapidly. There are various reasons why your thermostat may not be working correctly. It might be that the wiring has to be replaced, that the batteries need to be replaced, or that your thermostat has moved.

Related Questions and Answers

Can a bad flame sensor cause short cycling?

Flame Sensor Failure Corrosion may also affect flame sensors. This is due to the fact that your heater generates very little water throughout the heating cycle. This might cause corrosion and rust in your furnace over time, resulting in short cycling.

Is short cycling an emergency?

Short-cycling may indicate a problem, such as a refrigerant leak. The underlying issue is the damage short-cycling causes to your cooling system. It reduces the system’s service life, increases maintenance costs, increases energy consumption, and reduces home comfort.

Why does my furnace short cycle only at night?

Short-cycling: If your furnace goes off often at night, it’s possible it’s short-cycling. When your furnace is too big for your house, this occurs. If your furnace is short-cycling, it will turn on for a brief moment before shutting off. This hinders it from effectively heating your house.

Why is my furnace coming on every 5 minutes?

Cycle time is 2–5 minutes. A high-limit switch is a component in your furnace. The switch turns off the furnace if it becomes too hot. A clogged filter stops fresh, cold air from entering the furnace and being heated and distributed. It will soon overheat if there is no fresh air.

Why is my furnace kicking on every 10 minutes?

Bad Thermostat: A malfunctioning thermostat might cause your furnace to operate in cycles that are either too long or too short. Your thermostat might cause your furnace to operate sporadically if it senses the wrong temperature and does not transmit a cut-off signal quickly enough, or if the battery is expiring.

What is considered short cycling for a furnace?

When a furnace cuts off before reaching the target temperature, it is said to “short cycle.” If your thermostat is set to 72 degrees, the furnace will shut off at 65 or 68 degrees, but never reach 72 degrees. A furnace that cycles on and off too often is referred to as short cycling.

How do you know a thermostat is bad?

7 Signs That Your Thermostat Is Faulty Thermostat Isn’t Working. The air conditioner or furnace will not turn on. The heater or air conditioner will not turn off. Thermostat does not match the temperature of the room. Thermostat is not working. Cycling is short. Thermostat Loses Its Programed Settings

Why does my furnace keep shutting off after a few minutes?

A defective or unclean flame sensor is likely to be the reason of your furnace turning off after a few minutes. The purpose of this crucial component is to keep an eye on the gas burner. The furnace runs then turns off and begins again when it can’t detect that burner. This may be a rather simple repair.

Why won’t my furnace shut off?

Look for the fan settings on your thermostat. “ON” and “AUTO” should both be present. If your furnace refuses to turn off, the thermostat for the blower may be set to “ON.” Toggle the switch to “AUTO” to ensure that your furnace’s blower fan only operates when it’s time to heat.

What can cause the blower to come back on for a short time after cycling off?

This is usually caused by leftover heat from the furnace heat exchanger rising into and re-heating the plenum air, prompting the fan limit switch to turn the fan back on in an attempt to cool the system by prolonging the heat exchanger temperature purge cycle time.

How long should a furnace run per cycle?

ten to fifteen minutes

What causes short cycling?

Short cycling is often caused by frozen evaporator coils. When it’s too chilly outdoors, air conditioners might freeze up. This generally happens at night. A dirty filter or a mechanical issue may cause freezing in other circumstances. Shut off your computer, let it thaw fully, and then restart it.

Why does my furnace keep cycling on and off?

Switch with high limit (cause of furnace to be turning on and off repeatedly) The high limit switch is an internal furnace safety mechanism that prevents your furnace from overheating. This safety function will turn off your furnace and prevent harmful circumstances such as fires.

Why is my heat pump short cycling?

If airflow is hindered owing to filthy air filters, air duct obstructions, or bent fins on air vents, warm air will be retained, ultimately overheating your system. Short cycling is your unit’s technique of defending itself from overheating in certain situations.

Why does my furnace keep tripping the reset button?

A furnace reset button is an essential component of any HVAC system. The feature is essential for securely heating your house since it rapidly shuts off the unit. It’s possible that your furnace is overheating if the reset button on your furnace keeps tripping. This might suggest that furnace maintenance is required.

Why does my furnace run but not heat?

The most prevalent cause of furnace troubles is dirty filters. Dust and grime obstruct airflow, and if the filter becomes too clogged, the heat exchanger can overheat and shut down prematurely, preventing your home from heating up. Replace the filter if the blower is operating but no heat is going out.

How do you tell if you need a new thermostat in your house?

Signs You Need to Replace Your Thermostat The heating or cooling system is not turning on or off. The temperature is not accurate. Your energy bill has just increased. Temperature swings are common. The thermostat is at least ten years old.

Why is my heat not staying on?

Dirty flame sensor – The flame sensor is a vital part of your furnace because it detects whether or not the pilot light is operating correctly. The furnace will turn off if this sensor gets filthy. When troubleshooting a furnace that has abruptly stopped operating, this is one of the most prevalent issues HVAC experts encounter.

How do I clean the flame sensor on my furnace?

How to Clean a Furnace Flame Sensor Turn off the electricity to the furnace. Close the gas valve. Remove the flame sensor from the furnace. Using an emery cloth, clean the sensor. The flame sensor should be returned. Start the furnace again.

What do you do when your furnace keeps running?

What to do if your furnace won’t shut off: Check the thermostat setting. Examine the air filter. Consider weatherizing your home. Examine your ductwork. Examine the vents. Check the temperature. P. is the company to call when you need heating equipment installed, maintained, or repaired.

Why does my heat keep running?

Examine Your Air Filter Your heating system may work overtime due to a blocked or filthy air filter. It just continues running because it is unable to provide enough heat into your house. Every two to three months, the air filter should be cleaned and changed.

What are some possible causes of delayed ignition?

Moisture builds up in the furnace after a period of inactivity, causing delayed ignition. Moisture causes the firebox to rust, blocking the gas supply ports to the burners. If the ports get clogged, the burners farther down the line will not ignite.

Why does my furnace turn off after 15 minutes?

Airflow will be restricted if your air filter is too filthy. To minimize overheating, your furnace will then turn off early. Flat filters should be replaced every a month, and pleated filters every three months. Adding a Filter Reminder to your thermostat makes it simple to remember to change your filter.

How many times does a furnace cycle per hour?

A furnace can run two to three cycles in an hour, however this number might vary from three to ten if the weather is very cold.

How long should a furnace stay off between cycles?

In an ideal situation, a gas furnace would cycle on and off 3-8 times each hour. With furnaces, this is usually the most well-known scenario. However, if your furnace isn’t cycling off properly, we suggest seeing an expert.


The “furnace cycles on and off every 5 minutes” is a symptom of an electric furnace that is short cycling. The problem can be fixed by replacing the thermocouple.

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