Why a pilot goes out
Older standing-pilot heaters use a thermocouple, a thin metal probe that sits in the pilot flame and tells the gas valve it is safe to keep gas flowing. When the thermocouple wears out or is knocked out of the flame, the valve shuts the gas off and the pilot dies seconds after you let go of the button.
Newer low-emission heaters add a flammable vapor sensor and an air intake screen at the bottom of the tank. Lint, dust and pet hair, common in a Brea garage, can clog that screen and starve the burner of air, which trips the safety system. Some heaters also have a thermal switch that shuts the burner off if it senses heat or flame rolling out where it should not.
Common causes
| Cause | Typical sign | Who should fix it |
|---|---|---|
| Worn thermocouple or flame sensor | Pilot lights but goes out when the button is released | Licensed plumber |
| Dirty pilot orifice | Weak, yellow or flickering pilot flame | Licensed plumber |
| Clogged air intake screen | Burner shuts off after running a while | Cleaning per the manual, or a plumber |
| Tripped flame rollout or thermal switch | Heater will not relight, scorch marks near the burner door | Licensed plumber; the cause must be found first |
| Venting or draft problem | Soot, heat or fumes at the draft hood | Licensed plumber right away |
| Failed gas control valve | No pilot gas at all, other gas appliances work | Licensed plumber |
| Gas supply off or interrupted | No gas at any appliance | SoCalGas |
Safe things to check
What to ask the plumber
- Which safety device shut the burner off, and why?
- Is the venting drawing properly?
- Is the combustion air intake clean and unobstructed?
- Given the heater's age, is replacing the gas valve or sensor worthwhile?
- Did you check the gas connection for leaks after the repair?
Common questions
Can I replace a thermocouple myself?
It involves the gas control and burner assembly, so most owners leave it to a licensed plumber. A wrong fit or loose connection can leave the heater unsafe.
Why does my pilot go out when the garage door opens?
A strong draft can blow out a weak pilot, but a healthy pilot and correctly installed burner door should resist normal drafts. Have the pilot and thermocouple checked.
Is a yellow pilot flame a problem?
A pilot should burn mostly blue. A lazy yellow flame can mean a dirty orifice or poor combustion air, so have it checked by a licensed plumber.
General information for Brea, not a quote or professional advice. In an emergency, call 911.