A working pilot light is the heart of any gas water heater. Without it, the burner won’t ignite, and the hot water stops flowing. When the pilot light won’t stay lit, comfort, safety, and efficiency are all at risk. However, a common problem is a water heater pilot light not working, and the cause can range from something as small as a dirty pilot tube to something as serious as a failing gas control valve. This guide explains how the pilot light works, why it may fail, and what steps you can take.
What the Pilot Light Does
The pilot light is a small, steady flame located inside the gas water heater. Its job is simple but essential: it ignites the main burner when hot water is needed.
When you open a faucet, cold water enters the tank, and the thermostat signals for heat. The pilot flame touches the burner assembly, lighting the gas and heating the water. Without a pilot light, the burner never ignites, and you’re left with a cold shower.
It’s important to note that electric water heaters don’t use pilot lights. Instead, they rely on heating elements and thermostats. This distinction helps homeowners avoid chasing the wrong problem.
Signs Your Pilot Light Is Out or Not Working
Not every homeowner looks inside their water heater, so recognizing the symptoms of a failed pilot light is key. Common signs include:
- No hot water: The most obvious indicator. Without ignition, the tank never heats.
- Burner won’t ignite: You may hear the click of the igniter or try pressing the pilot button, but the burner stays off.
- Faint gas smell: A weak pilot or repeated failed ignitions can release a small amount of unburned gas. This should always be taken seriously.
- Status indicator: Some modern gas water heaters feature warning lights or error codes that signal a failed pilot.
Spotting these early helps you take the right next steps, even if that’s relighting the pilot yourself or scheduling service with a plumber.
7 Common Reasons the Pilot Light Won’t Stay Lit
A water heater pilot light can fail for several reasons, some minor and others indicating more significant system issues. Knowing the most frequent culprits helps you narrow down the cause.
1. Thermocouple Issues
The thermocouple is a safety device that detects if the pilot flame is burning. When it’s dirty, bent out of alignment, or completely faulty, it will shut off the gas supply, causing the pilot to go out. Soot, rust, or corrosion often builds up on the thermocouple tip over time, reducing sensitivity.
2. Dirty or Clogged Pilot Tube
The pilot tube delivers a steady flow of gas to the pilot orifice. Dust, dirt, or even spider webs can clog this narrow tube. A restricted flow produces a weak flame that flickers out easily, especially in drafty spaces.
3. Drafts or Airflow Issues
Gas water heaters rely on stable airflow through the draft diverter and venting system. Strong drafts from poorly sealed vent pipes, missing flue caps, or open garage doors can blow the flame out. A proper pilot light shield or wind guard helps protect against this.
4. Gas Supply Problems
A kinked or twisted flexible gas tube, a closed gas inlet valve, or low gas pressure from the utility can all interrupt supply. Inconsistent flow makes the pilot flame unstable. Checking other gas appliances in the home helps confirm whether it’s a local issue with the water heater or a broader gas line problem.
5. Faulty Control Valve or Pilot Assembly
The gas control valve regulates fuel to both the pilot and main burner. Worn-out internal parts or a failing regulator can prevent the pilot from staying lit.
Sometimes, the entire pilot assembly, including the orifice, thermocouple, and tubing, needs replacement.
6. Moisture or Condensation Inside the Heater
Water heaters installed in basements or garages often experience condensation buildup. Moisture dripping onto the pilot or thermocouple can extinguish the flame. Over time, this exposure also accelerates corrosion in the burner compartment.
7. Residual Gas Inside the Unit
After multiple failed lighting attempts, unburned gas can accumulate inside the combustion chamber. This can make relighting difficult and potentially dangerous. Always allow time for ventilation before retrying.
DIY Checks Before Calling a Plumber
Some pilot light problems have simple fixes that don’t require special tools. Homeowners can try a few safe steps before scheduling service.
Safety First
Always start by turning off the gas supply using the shut-off valve near the heater. Let the combustion chamber air out for several minutes to clear any residual gas. Ignoring this step increases fire and explosion risk.
Check for Drafts
Look around the draft diverter and venting system for signs of poor airflow. Gaps in vent pipes, missing chimney caps, or heaters placed in garages with frequent door openings can all create drafts that blow out the flame.
Inspect the Pilot Tube
Remove the access panel and locate the pilot tube. A buildup of dust, rust flakes, or spider webs often restricts gas flow. Lightly blowing compressed air through the tube can help clear blockages.
Look for Flex Tube Issues
Trace the flexible gas supply line. A kinked or twisted tube limits fuel delivery to the pilot assembly. Straightening the line or adjusting its position may restore flow.
Reset, According to the Manual
Many newer models include reset instructions on the access panel. Resetting the system may restore normal operation if the safety controls were tripped.
Watch Out for Gas Smells
A faint odor of gas near the unit requires immediate caution. Do not relight or troubleshoot until the area is ventilated. Persistent gas smells should always be left to a licensed plumber or utility technician.
Step-by-Step: How to Fix a Water Heater Pilot Light?
Different manufacturers use slightly different pilot assemblies, but most follow the same basic procedure. Always check the manufacturer’s manual first.
- Locate the Gas Control Knob – Usually found on the front of the gas valve. Turn it to the Pilot setting.
- Press and hold the Pilot Control – This sends gas into the pilot tube.
- Ignite the Pilot – Use the igniter button if equipped, or a long lighter if manual lighting is required.
- Hold for 30–60 Seconds – This gives the thermocouple time to detect the flame and keep gas flowing.
- Release the Control – The flame should stay lit. The thermocouple or control valve may need replacement if it goes out immediately.
- Turn the Knob to “On” – Once the pilot is stable, rotate the knob to On to allow the main burner to operate.
A steady blue flame indicates success. A weak, yellow, or flickering flame suggests a problem with gas pressure, dirty components, or airflow.
When to Call ProsWay (Don’t Delay on These)
Some pilot light issues signal deeper risks that go beyond DIY troubleshooting. Contact a licensed plumber immediately in these situations:
- Persistent Gas Smell or Hissing – Continuous gas odor points to a leak. Ventilate the area and avoid ignition sources until help arrives.
- Pilot won’t Stay Lit After Thermocouple Replacement – Indicates a faulty gas control valve or regulator, both requiring professional tools and parts.
- Soot, Rolled Flames, or Burn Marks – Signs of improper combustion, poor venting, or burner damage that increase fire and carbon monoxide risk.
- Backdraft Warnings – Warm flue gases spilling back into the room or a CO alarm sounding are urgent hazards.
- Repeated Outages in Windy Weather – May need a draft diverter adjustment, chimney cap, or wind guard installation.
- Older Units (10–12+ Years) – Frequent pilot outages often mean the heater is nearing the end of its service life. Replacement may be more cost-effective than repeated fixes.
ProsWay Plumbing & HVAC technicians handle all of these scenarios with proper testing equipment, replacement parts, and safety checks.
Preventing Future Pilot Light Problems
Preventive care goes a long way toward keeping your pilot light reliable:
- Annual Service – Have a plumber clean the pilot assembly, burner, and thermocouple.
- Maintain Combustion Airflow – Keep air intake areas around the heater clear.
- Add Chimney Cap or Baffle – Reduces wind-related outages in draft-prone homes.
- Check Vent Connections – Ensure venting is properly aligned and sealed after any repairs.
- Install CO Detectors – Place them near sleeping areas for added safety.
- Log Service Dates – Replace thermocouples proactively when wear is detected.
Conclusion
A pilot light that won’t stay lit is frustrating, but it doesn’t have to leave you without hot water for long. Many causes are simple, like a dirty pilot tube or a faulty thermocouple. Others require professional repair, especially when gas safety is involved. Hot water is too important for comfort and safety to risk guesswork.
Restore Reliable Hot Water with ProsWay Plumbing & HVAC!
ProsWay Plumbing & HVAC provides expert water heater repairs across Northern New Jersey. From thermocouple replacements to full gas control valve service, their licensed plumbers restore hot water safely and quickly. Call us now at (862) 260-5870 or Book Online today for fast, dependable water heater service and peace of mind.
