How To Light a Furnace Pilot Light
You’ll want to have these tools on hand to check the pilot light:
The pilot light on a gas furnace can go out because of drafts. To relight the pilot, follow the manufacturer’s instructions exactly; they are usually fastened to the furnace. If instructions for relighting the pilot are not provided, follow this general procedure:
Step 1: Find pilot light assembly. It typically has a gas valve with on, off, and pilot settings.
Step 2: Turn valve to off and wait three minutes.
Step 3: Switch valve to pilot setting. Hold lighted match to pilot opening while you push reset button on pilot control panel. Keep this button depressed until pilot flame burns brightly, then set valve to on position.
Step 4: If pilot flame won’t stay lit, opening may be clogged. Turn gas valve off, and clean opening with piece of fine wire. If it won’t stay lit after several attempts, you may have faulty thermocouple. If pilot flame still won’t stay lit, call your Hilton Head heating and cooling specialist.
Some furnaces have an electrical system to ignite the gas; in these systems there is no pilot light. Instead, an electric element heats up and ignites the burners. If this electric ignition system malfunctions, call a professional Hilton Head heating and cooling specialist.
If the pilot light won’t stay lit, the thermocouple — a safety device — might be malfunctioning. This is, once again, a situation where you may need to call your Hilton Head heating contractor.
Article Source: http://home.howstuffworks.com/how-to-repair-gas-furnaces2.htm