Call a pro if you re unsure about performing the tests yourself. If your furnace shuts off too often you could have a corroded or dirty flame sensor.
After 3 times the furnace goes into lockout and the only way to get it out of lockout is to turn the power switch off and on.
Furnace comes on then shuts off. Your furnace serves an important role in keeping your family comfortable. If the heat exchanger highlighted above gets too hot the furnace shuts down. So your furnace also has a flame recognition system including a flame sensor which detects the presence of a flame.
Try cleaning the flame sensor with a fine abrasive pad. It is essential that any work is done by an hvac specialist who has been trained to understand how the furnace works. Your furnace main burner ignites the main burner stays on for 8 to 10 seconds then shuts right back off your furnace tries this ignition sequence again and the same thing happens.
Thermostats near heat sources or in direct sunlight can warm too quickly signaling your furnace to shut off. A flame sensor lets your system know there s a flame when the gas valve is open. Once the heat exchanger overheats it trips the high limit switch which shuts the furnace down to protect it.
You should also test your thermostat to ensure it s working correctly. 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 could be a relatively easy fix.
If the flame sensor does not detect a flame the control board will shut off voltage to the gas valve to prevent the furnace from heating. It is not normal for a heating cycle to be so fast and short cycling can cause damage to the furnace. If there isn t a flame the sensor will shut off the gas valve to keep the gas from getting into your house.
Sometimes if the flame sensor is dirty it will fail to detect a flame. Obviously if you were just dumping gas into your furnace but the gas was not being burned this could be dangerous when the flames finally do come on. The furnace starts to heat the home but turns off again quickly after only a short amount of time has passed.
A common reason a furnace short cycles is because the heat exchanger the part that heats your air is getting too hot due to a lack of airflow. A furnace that starts then stops is a common issue also known as short cycling. If your furnace comes on then shuts off and you don t feel comfortable contact us for an evaluation of the problem.
This vital component is designed to keep an eye on the gas burner. If the furnace still doesn t heat replace the flame sensor. Testing your thermostat can involve handling live wires.
When it cannot sense that burner the furnace runs then shuts off and starts again. If no flame is present within 4 second the system will shut off.