Pilot lights are aptly named because without them your gas-heated appliance is figuratively grounded. You should take the opportunity to inspect the status of your pilot light if you suspect your furnace is having problems. The flame of a natural gas pilot light should be blue with a blue-green core. It is permissible to have a slight cone of yellow at the top, but too much yellow means it is time to correct the pilot light. Too much blue is also a sign of problems.
Things You'll Need
- Open-end wrench
Remove the main furnace access panel to inspect the flame produced by the pilot light. If there is no flame at all, turn off both the gas supply to the furnace and the pilot gas shutoff switch if the furnace has one. Give the pilot about 10 minutes to cool off and then remove the cover. Relight the pilot light according to the instructions that should be found on the back of the access cover.
Check to make sure the pilot flame is not too weak, which is indicated by an overly blue flame. If the flame is making more noise than normal, this is a sign of its being too strong. Locate the pilot adjustment screw on the control housing inside the furnace. Check your manual if you have trouble locating the control housing.
Turn the screw counterclockwise on most models to adjust the flame stronger and clockwise to adjust the flame weaker. Try to get the screw in the spot where the flame has a small yellow tip. If the flame appears even after you have adjusted it to become stronger, you will need to clean the orifice of the pilot jet.
Turn off the power and close the gas supply once again. Wait 30 minutes to make sure the parts have cooled enough to be handled. Locate the control housing. Use an open-end wrench to loosen and remove the thermocouple. Hold the pilot gas line with a pair of pliers as you also remove it.
Unscrew and remove the pilot bracket that is located near the burner tubes. Remove the pilot gas line and the thermocouple from this bracket.
Clean the outside of the pilot jet nozzle with a toothbrush. Use a soft wire brush or pipe cleaner to clean out deposits stuck inside the nozzle. Be very care to avoid scratching or chipping the pilot light nozzle.
Reassemble the pilot gas line and thermocouple back onto the bracket. Reattach the entire pilot light assembly back onto the control housing. Turn the gas supply and power back on and inspect the flame to see if cleaning the nozzle has made the flame burn too brightly. Follow the instructions to readjust the flame if it is too strong.