Whether your heating system runs on natural gas or liquefied petroleum (LP), the system works in the same straightforward, simple manner. Gas enters the furnace via a thermostatically-controlled valve. The gas goes to burners, which are ignited by a constantly-burning flame, known as a pilot light. Many times, when you have trouble with your HVAC system, it is due to issues with the pilot light.
What Can Go Wrong?
If your pilot light won't stay light, relighted, or keeps going out, your gas furnace cannot run properly. Gas furnaces have a thermocouple. It is a safety device that detects heat from the ignition system and only allows gas to flow when enough heat is present for combustion. To make sure the pilot light stays lit, make sure that the flame is lapping over the thermocouple. If it is not, you can adjust the burner flame with only a few steps.
- Remove any cap covering the pilot light adjusting screw
- Turn the screw clockwise to to decrease the flame, and counterclockwise to increase it
- Loosen any lock screws
- Open air shutter until flame lifts from the tube
- Close the shutter until it settles back and is burning the correct color
The correct burner flame is a distinct blue-green cone within a softer blue flame. If the flame is getting too much air, the inner flame will be sharp blue. If the flame is not getting enough air, the flame will have a yellow tip. A yellow-tipped flame may be a sign of an obstruction in the fuel line, which requires a call to an HVAC repair technician.
What Type of Maintenance Is Needed?
Regular maintenance can help keep your pilot light lit and your furnace working properly. You should clean the burners on older gas furnaces once per year, and burner on newer furnace every few years. Ignition problems and clogged burners are the root cause of many furnace troubles. Cleaning the burners is not a difficult job, and you can remove the burner tubes for cleaning in most furnaces. There are a few steps to follow when cleaning burners.
- Shut off gas and power
- Unscrew burner tubes from the supporting brackets
- Gently twist and lift tubes free
- Vacuum or brush the tubes clean
- Avoid damaging burner ports
- Use a stiff wire to carefully clear any clogged ports
Once you're finished, replace the burner tubes and use the furnace as usual.
If you are having trouble getting your pilot adjusted, you can call an HVAC repair tech in to do an inspection. If you smell gas, turn off the gas to your home at the main shutoff valve and call the gas company before calling an HVAC technician.