The proper operation of your furnace directly affects your heating costs. One important measure of this operation is the colour and movement of the burner's flames. The burners are adjusted by the installer for the proper air/fuel mixture. When operating properly, the flame should be blue in colour and stable.
Orange or Yellow Tips
If the tip of the flame is a distinct orange or yellow in colour, this can indicate that the burner needs adjusting or cleaning. The colours may mean that the burner is delivering inadequate primary air or the air opening is dirty, which should be determined by a certified heating technician.
When the flame is lifting off the burner surface, this can indicate that there is excessive primary air. The lifting can also be accompanied by a noise at the flame. Combustion will be incomplete and the efficiency of the furnace affected.
A flame that waves back and forth can be caused by an unstable air supply. More seriously it can also indicate a crack in the heat exchanger, which would allow combustion products into the home's air supply. A secondary indicator of a cracked heat exchanger is if the flame moves more when the furnace fan kicks on. Only a technician with a gas combustion analyzer can determine if the heat exchanger is damaged.
A lazy flame that rolls around the combustion chamber and/or is not vertical is evidence that the burner may be over firing. It can also show a venting problem or inadequate air supply. This incomplete combustion can cause the burner's pilot to extinguish, leaving the house without heat.