If your furnace keeps shutting off, it could be
due to low airflow
. There are several indirect issues that cause low airflow. Dirty Air Filters. If you don't change your air filters often enough, the filters will become dirty and clogged, which means the heat exchanger retains heat and eventually causes it to overheat.
Why does my oil burner keep turning off?
Obstructed airflow
: Sometimes the reset button gets tripped because the furnace isn't receiving enough airflow. … Dirty flame sensor rod: Every now and then, the flame sensor rod gets dirty and shuts the furnace off. Make sure you wipe it off regularly. Low fuel: Low fuel is also a common cause of burner failure.
Don't hit “reset”
more than twice
. The process pumps oil into the burner chamber, where it can accumulate if you have no ignition. Then when the furnace finally does start, it can do so explosively. So if the button won't reset, or quickly pops up again, it's time to call a professional repair service.
Why does my furnace keep shutting off after a few minutes?
If your furnace turns off after a few minutes, there is a good chance it is caused
by a faulty or dirty flame sensor
. This vital component is designed to keep an eye on the gas burner. When it cannot sense that burner, the furnace runs then shuts off and starts again.
Why does my furnace turn on then off right away?
Your furnace turns on, runs for a few minutes and then shuts off. … Typically, a furnace keeps turning off and on (or “short cycling”) like this because of one of these problems:
Heat exchanger is overheating due
to low airflow. Dirty flame sensor rod.
Why does my heater keep running after it has reached the set temperature?
When your furnace keeps running after the temperature has been reached:
Check the blower motor
– Your forced air heating system uses a blower to push air through ducts and into your living space; sometimes, the blower runs at the same time that your furnace is heating the air, but sometimes it runs on its own.
Why does my furnace shut off after 15 minutes?
Short-cycling is when a heater doesn't complete its regular heating cycle and turns off early. A full heating cycle for a furnace or heat pump is usually around 15 minutes or more. If your heater keeps turning off after only five minutes, that's too short—no matter how low you've set the thermostat.
How do I get my furnace out of lockout mode?
Though lockout mode errors and resets do vary from manufacturer to manufacturer, most use a simple reset procedure that involves turning power off to the furnace for thirty seconds or longer and turning it back. The
interrupted power
supply clears the lockout and will allow the unit to attempt normal operation again.
How do you restart a furnace after running out of oil?
- Step 1: Fill the Fuel Tank. …
- Step 2: Hit the Reset Button. …
- Step 3: Turn off the Furnace. …
- Step 4: Collect Your Tools. …
- Step 5: Find the Bleeder Valve. …
- Step 6: Attach Nylon Tubing. …
- Step 7: Turn on the Furnace and Unscrew the Valve. …
- Step 8: Tighten the Valve.
Can a bad thermostat cause a furnace to short cycle?
A faulty thermostat can
be a possible culprit for short cycling. If you're experiencing a furnace short cycling, the first and easy thing you can do is check your thermostat to see if it's performing correctly. Many times, a homeowner may forget to switch their thermostat over to the heating mode.
How do you fix a short cycle furnace?
The easiest way to fix a furnace that is short cycling is
to remove the flame sensor to clean it
. Use a sponge or brush to remove the dirt from the sensor. After the part is clean, follow the manufacturer's instructions to insert the flame sensor into the furnace.
How long should furnace run before shutting off?
With all that being said, if there are no extreme factors involved, the average run time for a furnace is
10-15 minutes per cycle
. Your furnace may need to run two to three times an hour to maintain your desired temperature if your home has average insulation.
How do I know if my fan limit switch is bad?
The most common sign of a malfunctioning limit switch is
the continuous operation of your furnace's blower
. Just as the limit switch won't allow the fan to turn on until the warm air has reached the right temperature, the limit switch also shuts down when the air cools to a certain temperature.
How do I know if my flame sensor is bad?
- Switch off the power to your furnace.
- Close the gas valve.
- Take out the mounting screw.
- Carefully pull out the sensor.
- Inspect the sensor: if the insulation is intact but appears sooty, burnt or slightly corroded, it might only require cleaning.
What does it mean when your furnace keeps running?
Some other problems that may cause a furnace to run constantly include a clogged furnace blower or a furnace blower/motor that needs
lubrication
—both of these issues will force your furnace to work ineffectively. Also, be sure to check that the fan switch on your thermostat is set to AUTO, not ON.
