Gas furnaces have pilot lights and they must be lit and working properly in order for the furnace to operate. When the pilot light goes out two things can happen: Gas can escape without burning and the furnace will blow cold when it should be blowing warm air.
If you own a gas furnace, you have a pilot light. Pilot lights can be a bit of a mystery to people. They know they're supposed to be lit. They know when the pilot light goes out the furnace or hot water heater won't work properly. But that's about all they know.
Frequently, problems with gas furnaces involve the pilot lights. There are several reasons why pilot lights go out, and that's why you should check your pilot light at least once a year. The furnace may not be operating properly and the gas flow has been interrupted. A power outage can affect gas furnace operation which in turn affects the pilot light. Of course, simple drafts can blow pilot lights out too.
Related to pilot lights is the thermocouple. The thermocouple insures the gas is cut off if the pilot light goes out. When pilot lights won't say lit, it can be due to faulty thermocouples. To relight a pilot light, first turn the valve to the pilot setting. Using a match or special lighter, push the reset button until the pilot light is lit again. Once you have a steady flame, turn the valve to the on position.
Pilot lights should burn steadily without interruption. If the flame wavers, it means the gas flow is being interrupted somehow, the pilot light opening is clogged or there's a draft that needs to be eliminated. Your regular furnace maintenance procedures should include checking the pilot lot regularly to ensure it's burning the way it should.
Another thing you should check is the height of the pilot lights. The flame should be no higher than 2 inches and no shorter than 1 ½ inches. If it is too short or too high, the electronic control may not be working properly.
Pilot lights are simple components, but they have to work properly in order for the furnace or water heater to work properly. You can't forget to check the pilot lights on your appliances on a regular basis. Good maintenance procedures will insure your units are always operating efficiently.
For more information on pilot lights