Gas Furnace Turns On And Off Quickly

A gas furnace that turns on and off quickly or is short cycling, is most likely due to a bad flame sensor. If the flame sensor does not detect the flame it will turn off the furnace to prevent a gas leak. Other causes include a dirty air filter or a bad thermostat. Make sure your air filter is clean and replace if needed and check to make sure your thermostat is working properly. If the problem persists call a service technician. It is recommended to repair this problem in 1 - 3 weeks. Estimated repair costs including labor, parts and service fees are $100 - $300.

Severity

Moderate

What It Means

The furnace is turned off as the flame sensor cannot detect the flame. You will be left without any heat.

Safe To Use

The furnace is not safe to use if the burning smell persists and should be turned off immediately at the thermostat and the breaker.

Estimated Repair Costs (including service fees)

• Replace Flame Sensor(Professional):$100 – $300

Causes

Causes include a dirty or damaged flame sensor.

Repair vs Replace

You should repair your furnace for this problem as you may just need to have the flame sensor replaced.

Prevention

Change your air filters every three months, make sure all your air ducts are clear and schedule annual maintenance to clean the sensors.