Furnace flames control your unit's
How Long Should a Furnace Flame Stay On? Once you turn on your furnace, the system will begin its heat cycle. Furnaces tend to run in cycles lasting between 10 and 15 minutes. The typical cycle frequency is two or three full cycles per hour until your home reaches the temperature on your thermostat.
The flame should stay on throughout the entire cycle, which takes 10 to 15 minutes to complete.
Are your furnace burners only coming on for a few seconds? This is the most common furnace problem which also happens to be the easiest thing to fix! Every furnace is different but almost all of them have a flame sensor. If your flame sensor is dirty or covered in a layer of dust, it will shut the burners off after lig.
Reasons why your furnace keeps turning on and off:
Temperatures outside of home. Improper insulation. Faulty thermostat. Dirty flame sensor.
With an effective air delivery system and a well-insulated home, this should be long enough to establish your preferred temperature throughout the building. After resting for approximately five to 10 minutes, your furnace will likely cycle on again.
While it should cycle throughout the day, clicking on too frequently may indicate a problem. Homeowners often find themselves wondering, "How often should my furnace cycle?" The answer lies in a gray area. On average, furnaces should kick on and turn off anywhere from three to eight times per hour.
Blocked vents or a clogged air filter may cause your furnace to run and then shut off too early. It's easy to fix these issues on your own. You should change your furnace filter at least once every three months. Follow our guide to do it yourself.
HVAC maintenance companies explain that a furnace will normally perform an average of two to three cycles in an hour, with each cycle lasting 10 to 15 minutes. But to keep temperatures at a comfortable level during cold weather, a furnace might need to increase this range to three to 10 cycles.
In addition to having a blue color, your furnace flame should be steady. Flickering, wavering, and any other indication of an odd flame pattern are likely signs of combustion problems.
Your electric stove is equipped with a component known as the “infinite switch.” The infinite switch regulates the power flowing to your burner, allowing you to select just the right heat level—low, medium, or high. However, there are times when this switch may malfunction, resulting in a burner stuck on full heat.
#1 Flame Sensor
If dirt or dust covers the sensor, the flame isn't detected, and the furnace shuts down. Sometimes all that is needed is a simple cleaning of the flame sensor, but it may also be worn out and need to be replaced.
If your flame is yellow or orange, or if you see pops of yellow or orange, that is a sign that you have a combustion problem that should be addressed by a professional. Long streaks of any color, such as yellow, orange, or green means your furnace needs adjustment or cleaning from a professional HVAC technician.
The pilot flame should touch the thermocouple at a specific level. If the flame is blue and weak, and barely reaches the thermocouple, it needs to be stronger. If it extends well above the thermocouple, it's too strong.
Generally, a furnace cycle lasts anywhere between three to 10 times every hour; however, the frequency changes depending on several factors. If your furnace is cycling on and off more frequently than it should, there could be a problem with one of its internal components.
To begin, ensure that all the filters of your furnace are clean. Also, get the filters replaced every few months to ease the burden on your HVAC system and ensure that fresh air comes filtered into your home. Another common cause of your furnace turning on and off after a few minutes is a faulty pressure switch.
Flame sensors have an average lifespan of about five years. Therefore, you can expect to need to replace it at least twice before replacing your entire heating system.
There is a work-around to waiting. If there is no safety risk (like a gas leak), a furnace can be reset to bypass this wait. Turn off the furnace's power switch and wait 10 seconds before turning it back on.
Furnaces typically run for about 10 to 15 minutes in moderate weather. Extreme cold can result in longer cycle times.
It's common for your furnace to kick on more frequently in cold weather. While it's okay if your furnace cycles on and off several times every hour, it shouldn't cycle on and off more than 8-10 times. If it does, this is known as short cycling, and it's a sign that something in your heating system needs to be fixed.
Short cycling is a common sign of a bad flame sensor. The sensor thinks that there isn't a flame, so it shuts off the gas as a safety mechanism.