Few things are more frustrating than a pilot light that won't stay lit. You light it, it burns for a moment, then goes out as soon as you release the button. This common problem affects gas water heaters throughout Charleston, Mount Pleasant, and Daniel Island. Here's what causes it and how to fix it.
How the Pilot Light System Works
Before troubleshooting, it helps to understand how your pilot light system operates:
- Pilot light burns continuously - A small flame that stays lit 24/7
- Thermocouple monitors the flame - A safety sensor that detects whether the pilot is lit
- Gas valve controls flow - Opens to allow gas only when the thermocouple confirms the pilot is lit
- Main burner ignites - When the thermostat calls for heat, gas flows to the main burner and the pilot ignites it
When any part of this system fails, the pilot light won't stay lit.
Common Causes and Solutions
1. Faulty Thermocouple (Most Common)
What It Is: The thermocouple is a thin metal rod that sits in the pilot flame. It generates a tiny electrical current when heated, signaling the gas valve that the pilot is lit.
Symptoms:
- Pilot lights but goes out when you release the button
- Pilot stays lit only while holding the button
- Thermocouple looks bent, corroded, or damaged
Why It Fails:
- Age and wear (typical lifespan 5-10 years)
- Corrosion from salt air (common on Sullivan's Island and Isle of Palms)
- Physical damage
- Soot buildup
Solution: Thermocouple replacement is the most common fix. It's a $20-$50 part, but proper installation is important for safety. Professional replacement typically costs $150-$200 in the Charleston area.
2. Dirty or Clogged Pilot Tube
What It Is: The pilot tube delivers gas to the pilot light. If it's clogged, insufficient gas reaches the pilot.
Symptoms:
- Weak, flickering pilot flame
- Pilot flame is yellow instead of blue
- Pilot won't light at all, or lights weakly
Why It Happens:
- Dust and debris accumulation
- Spider webs (common in garages)
- Corrosion
Solution: A professional can clean the pilot tube and orifice. This is often done during routine maintenance and typically costs $75-$150.
3. Thermocouple Position Issues
What It Is: The thermocouple must be positioned correctly in the pilot flame to sense heat properly.
Symptoms:
- Pilot lights but thermocouple doesn't stay hot enough
- Intermittent pilot outages
- Pilot goes out shortly after lighting
Why It Happens:
- Thermocouple gets bumped out of position
- Improper installation
- Thermal expansion over time
Solution: The thermocouple needs to be repositioned so its tip is fully engulfed in the pilot flame. This is a simple adjustment for a professional.
4. Drafts and Ventilation Issues
What It Is: Strong air currents can blow out the pilot light.
Symptoms:
- Pilot goes out during windy weather
- Pilot goes out when garage door opens
- Pilot goes out when HVAC system runs
Why It Happens:
- Water heater location has strong drafts
- Improper venting creates downdrafts
- Nearby HVAC returns create air movement
Solution:
- Improve draft shielding around the burner area
- Check and repair venting issues
- Relocate draft-causing equipment if possible
This is particularly relevant for Daniel Island and Mount Pleasant homes with water heaters in attached garages.
5. Faulty Gas Valve
What It Is: The gas valve controls gas flow to both the pilot and main burner.
Symptoms:
- No gas flow to pilot at all
- Pilot lights but main burner won't ignite
- Gas smell without visible flame (dangerous)
Why It Happens:
- Internal valve failure
- Electrical component failure
- Age (typical lifespan 10-15 years)
Solution: Gas valve replacement is a significant repair, typically $200-$400 for parts and labor. On older water heaters, replacement of the entire unit may be more economical.
6. Flex Tube Problems
What It Is: The flex tube connects the gas valve to the burner assembly.
Symptoms:
- Pilot won't light despite gas being on
- Weak gas flow to pilot
- Visible kinks or damage in the tube
Solution: Flex tube replacement is relatively simple and inexpensive ($50-$100 installed).
How to Relight Your Pilot Light
If your pilot light has simply gone out (no underlying problem), here's how to relight it:
Step 1: Locate the Gas Control Valve
Find the gas control knob on your water heater. It typically has three positions: ON, OFF, and PILOT.
Step 2: Turn to Pilot
Turn the knob to PILOT. You may need to push in on the knob to turn it.
Step 3: Light the Pilot
- With electronic igniter: Press the igniter button while holding the control knob in
- With manual ignition: Use a long lighter or match to light the pilot while holding the knob in
Step 4: Hold for 30-60 Seconds
Keep holding the control knob in for 30-60 seconds after the pilot lights. This heats the thermocouple.
Step 5: Release and Test
Release the knob. The pilot should stay lit. If it goes out, wait 5 minutes and try again. If it still won't stay lit, you likely have a thermocouple or other issue.
Step 6: Turn to ON
Once the pilot stays lit, turn the control knob to ON. You should hear the main burner ignite when the thermostat calls for heat.
When to Call a Professional
Relight the pilot yourself only if you're comfortable doing so. Call Water Heater Doctors if:
- The pilot won't stay lit after multiple attempts
- You smell gas when the pilot is out
- The pilot flame is yellow or orange (should be blue)
- You see soot or scorching around the burner area
- The water heater is making unusual noises
- You're uncomfortable working with gas appliances
Gas Safety Warning
If you smell gas:
- Do NOT try to light the pilot
- Do NOT flip any light switches
- Leave the house immediately
- Call your gas company from outside
- Do not return until cleared by professionals
Preventing Pilot Light Problems
Regular Maintenance
Annual maintenance includes:
- Thermocouple inspection and cleaning
- Pilot assembly cleaning
- Burner inspection
- Venting check
This prevents most pilot light issues and extends your water heater's life.
Keep the Area Clean
Dust, lint, and debris can clog the pilot assembly. Keep the area around your water heater clean, especially in garages where dust accumulates.
Address Draft Issues
If your pilot goes out frequently during certain conditions (wind, HVAC running), address the draft source rather than just relighting repeatedly.
Consider Upgrade Options
Newer gas water heaters often use electronic ignition instead of standing pilots. Benefits include:
- No pilot to go out
- Better energy efficiency
- More reliable ignition
Tankless water heaters also eliminate standing pilot concerns entirely.
Cost to Fix Pilot Light Issues
| Problem | Typical Cost |
|---|---|
| Thermocouple replacement | $150-$200 |
| Pilot tube cleaning | $75-$150 |
| Gas valve replacement | $200-$400 |
| Thermocouple repositioning | $75-$125 |
| Full maintenance service | $100-$175 |
Service Areas
Water Heater Doctors repairs gas water heaters throughout the Charleston Lowcountry:
Mount Pleasant - All neighborhoods including Coleman Boulevard, Park West, Dunes West, I'On, and Belle Hall.
Daniel Island - Complete residential and commercial coverage.
Charleston - Downtown, West Ashley, James Island, Johns Island, North Charleston.
Sullivan's Island - Full service for island homeowners.
Isle of Palms - Including Wild Dunes and all residential areas.
FAQ: Pilot Light Problems
Why does my pilot light keep going out? The most common cause is a failing thermocouple. Other causes include drafts, dirty pilot tube, or gas valve issues.
How much does it cost to fix a pilot light that won't stay lit? Most pilot light issues cost $150-$250 to repair. Thermocouple replacement is the most common fix.
Can I replace the thermocouple myself? While technically possible, we recommend professional service for gas appliances. Improper installation can create safety hazards.
How long should a thermocouple last? Typically 5-10 years. Coastal homes on Sullivan's Island and Isle of Palms may see shorter lifespans due to salt air corrosion.
Should I upgrade to a water heater without a pilot light? If your water heater is older and you're tired of pilot light issues, upgrading to a unit with electronic ignition or a tankless system eliminates the problem entirely.
Tired of relighting your pilot? Water Heater Doctors provides fast, reliable gas water heater repair throughout Charleston, Mount Pleasant, Daniel Island, Sullivan's Island, and Isle of Palms. Call (843) 990-6524 for same-day service.