Pilot Light Won't Stay Lit
Quick Answer
A pilot light that won't stay lit is usually caused by a bad thermocouple - a safety device that costs $10-30 to replace. Other causes include a dirty pilot orifice, drafts, or gas supply problems. Always ensure you smell no gas before attempting repairs.
Safe Checks You Can Do
- 1Relight properly - Hold the reset button for 60 seconds after lighting to heat the thermocouple.
- 2Check for drafts - Look for sources of air movement that could blow out the pilot flame.
- 3Inspect thermocouple position - The tip should be directly in the pilot flame. Bend gently if misaligned.
- 4Clean pilot assembly - With gas off, use compressed air to clear dust from the pilot orifice.
Likely Causes
- Faulty thermocouple
The thermocouple senses the pilot flame. If worn or faulty, it shuts off gas even when pilot is lit.
- Dirty pilot orifice
Dust and debris can clog the small opening, creating a weak flame that can't heat the thermocouple.
- Drafts
Strong air currents from vents, windows, or the chimney can blow out the pilot flame.
- Gas supply issues
Low gas pressure or a partially closed valve can cause the pilot to go out.
- Flex tube kink
The small tube supplying gas to the pilot may be kinked, restricting gas flow.
When to Call a Pro
- You smell gas anywhere near the furnace
- The pilot won't light at all
- You're not comfortable working with gas appliances
- You've replaced the thermocouple and problem persists
- The pilot flame is yellow instead of blue
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