Before anything else: if you smell gas, don't relight anything. Leave the house, and call NW Natural's emergency line or 911 from outside.
A pilot light is a small, always-on gas flame that lights the main burners when your thermostat calls for heat. When it goes out, the furnace can't make heat. The good news is that relighting a standing pilot is usually a five-minute job.
First, Check Whether You Have a Pilot Light
Most furnaces built in the last 25 years don't have a standing pilot. They use electronic ignition, either a hot surface igniter that glows orange or an intermittent pilot that lights only when heat is called for. If you look through the burner window and don't see a small blue flame or a pilot assembly with a knob marked PILOT, you have electronic ignition, and there's nothing to relight. Skip to the section on electronic ignition below.
How to Relight a Standing Pilot Light
Always follow the lighting instructions printed on the label inside your furnace door first. They're specific to your model. The general steps look like this:
- Turn the thermostat down so it isn't calling for heat.
- Turn the gas control knob to OFF and wait at least 5 minutes so any gas in the burner area clears out.
- Turn the knob to PILOT and press it down. This lets gas flow to the pilot only.
- Light the pilot while holding the knob down. Use the built-in igniter button if there is one, or a long-reach lighter.
- Keep holding the knob for 30 to 60 seconds after the flame lights. This heats the thermocouple, the safety sensor that keeps the gas valve open.
- Release slowly. If the flame stays lit, turn the knob to ON and set the thermostat back to heat.
Why the Pilot Keeps Going Out
If the pilot lights but goes out as soon as you let go, or it keeps going out every few days, something is wrong. The usual causes:
- A worn thermocouple. This is the most common cause. The thermocouple tells the gas valve the pilot is lit. When it weakens, the valve shuts the gas off.
- A dirty pilot opening. Dust and soot shrink the flame so it no longer heats the thermocouple. A healthy pilot flame is steady and mostly blue.
- Drafts. A strong draft near the furnace closet can blow the pilot out.
- A gas supply problem. If other gas appliances aren't working, the problem is upstream of the furnace.
If You Have Electronic Ignition
With electronic ignition, a no-heat problem usually comes from a failed igniter, a dirty flame sensor, or a safety lockout. Turn the power switch on the furnace off for 30 seconds and back on to reset it. If it still won't light, look for a blinking light code through the small window on the furnace and call us with the number of blinks.
