If your furnace has a pilot light, the thermocouple should be kept clean and the flame properly adjusted to ensure energy efficiency and extended furnace life. Check the standing pilot light before each heating season for proper air and fuel mixture and flame color. Here is how you can inspect and repair or adjust your standing pilot light for the best furnace operation.

Inspecting the Pilot Light Flame

The color of a proper pilot light flame can vary a bit but whether your furnace uses natural gas or propane as a fuel, the color should be blue with perhaps a tinge of yellow at the tip of the flame. A bluish-green flame can also result from rust or dirt. To inspect the operation of the standing pilot light. If the pilot light does not light or does not stay lit, then replace the thermocouple. Watch for any live power inside the furnace once the cover is removed.

Adjusting the Flame

There is usually a small screw on the pilot valve body that will adjust the standing pilot flame. You may have to refer to the furnace manufacturer’s instructions to find the screw. Turn the screw as needed to adjust the flame throw. There are several flame abnormalities you should look for: 

A yellow flame is caused by a lack of air and incomplete combustion. It can be caused by a dirty pilot tube tip. You can usually clean this debris away with a small screwdriver or nail tip.A split flame is caused by dirt inside the pilot tube. Take a needle or small nail and gently clean the tube.A flickering or wavering flame is usually caused by a draft. Check to see if there are obvious sources of drafts in the room. Sometimes this flickering is because the furnace’s cover panel has been removed, but it may also indicate a source of the ongoing draft that should be remedied.