Pilot Light Won't Stay Lit
Diagnose thermocouple failures, gas issues, and draft problems
Quick Answer
Pilot lights that won't stay lit are caused by faulty thermocouples (75%), dirty pilot assemblies (15%), or draft/ventilation issues (10%). If the pilot stays lit for 30-60 seconds then goes out, the thermocouple needs replacement. Immediate pilot outage indicates gas supply or orifice problems. Due to gas safety concerns, professional repair is strongly recommended.
Professional service recommended for this issue
Understanding Pilot Light Systems
How Pilot Lights Work
- • Continuous flame: Small gas flame burns 24/7
- • Thermocouple sensor: Generates electricity from heat
- • Safety valve: Held open by thermocouple current
- • Fail-safe design: No flame = gas shuts off
- • Ignition source: Lights main burner when needed
Why Pilots Fail to Stay Lit
- • Weak thermocouple: Insufficient voltage generated
- • Poor flame contact: Thermocouple not heated properly
- • Dirty components: Reduced gas flow or sensing
- • Draft interference: Wind blows out flame
- • Gas pressure issues: Too low to maintain flame
Energy Note: Standing pilots waste $10-20/month in gas. Many Southlake, Westlake, Grapevine homeowners upgrade to electronic ignition systems for efficiency and reliability.
Thermocouple Failure - The #1 Cause
Understanding Thermocouple Function
How It Works:
- Pilot flame heats thermocouple tip
- Heat generates 20-30 millivolts
- Voltage energizes gas valve magnet
- Magnet holds safety valve open
- No heat = no voltage = gas shuts off
Failure Symptoms:
- • Pilot lights but goes out after 30-60 seconds
- • Must hold button longer to keep pilot lit
- • Pilot increasingly difficult to light
- • Works sometimes but not others
- • Complete failure - won't stay lit at all
Lifespan: Thermocouples typically last 3-5 years. In dusty Texas conditions with frequent use, expect 2-4 year replacement intervals.
DIY Thermocouple Checks
Visual Inspection:
- • Check tip isn't bent away from pilot flame
- • Look for white/green corrosion on tip
- • Ensure connection at gas valve is tight
- • Verify pilot flame envelops upper 3/8" of tip
Simple Cleaning:
- Turn off gas and let cool completely
- Remove thermocouple from pilot assembly
- Gently clean tip with fine sandpaper
- Reinstall ensuring proper position
- Test pilot operation
Success Rate: Cleaning helps 20% of cases. If pilot still won't stay lit, replacement is needed.
Other Pilot Light Failure Causes
Dirty Pilot Assembly (15% of failures)
Common Contaminants:
- • Spider webs in pilot tube
- • Dust/debris in orifice
- • Rust flakes from gas line
- • Insect nests in assembly
- • Carbon buildup on components
Symptoms:
- • Weak, yellow pilot flame
- • Pilot hard to light initially
- • Flame lifts off pilot hood
- • Inconsistent flame size
- • Pilot goes out randomly
Draft & Ventilation Issues (10% of failures)
Draft Sources:
- • Wind through cabinet gaps
- • Downdrafts in vent stack
- • Negative pressure in room
- • Missing heater door
- • Oversized ventilation
Solutions:
- • Install wind guards
- • Seal cabinet gaps
- • Check door gaskets
- • Redirect air currents
- • Professional vent sizing
Gas Supply Problems (5% of failures)
Supply Issues:
- • Low gas pressure
- • Partially closed valves
- • Undersized gas lines
- • Regulator problems
- • Peak demand pressure drop
Warning Signs:
- • Other gas appliances affected
- • Weak pilot from start
- • Problems during cold snaps
- • Issues at specific times
- • Yellow flame color
Mid-cities west of DFW Airport Note: Gas pressure drops during extreme cold when demand peaks. This affects pilot light stability.
Pilot Light Safety Warnings
- •Never attempt pilot repairs if you smell gas - evacuate and call 911
- •Always turn off gas supply before any pilot light work
- •Do not use matches or lighters near gas leaks
- •Never bypass or disable the thermocouple safety system
- •Repeated pilot failures may indicate dangerous conditions
- •Carbon monoxide can accumulate from improper combustion
If you smell gas: EVACUATE immediately and call your gas company's emergency line
What You Can Safely Try
Safe DIY Steps:
- Check pilot lighting instructions on heater
- Ensure gas valve is fully open
- Clean thermocouple with sandpaper
- Adjust thermocouple position in flame
- Remove obvious debris from pilot area
- Check for drafts affecting pilot
- Tighten thermocouple connection
Call Professional For:
- ✗ Gas odors at any time
- ✗ Pilot won't light at all
- ✗ Thermocouple replacement needed
- ✗ Gas pressure testing required
- ✗ Pilot assembly cleaning/replacement
- ✗ Any internal heater work
- ✗ Electronic ignition upgrade
Modern Alternative:
Consider upgrading to electronic ignition. Eliminates pilot light problems, saves $120-240/year in gas, and improves reliability. Upgrade cost $400-800 pays for itself in 3-4 years.
Professional Pilot Light Diagnosis
Observe Pilot Light Behavior
Document exactly how and when pilot fails
⚠️ Warning: Gas odors indicate leaks - evacuate and call emergency services
Test Thermocouple Function
Check the most common failure point
⚠️ Warning: Thermocouple generates millivolts - multimeter testing requires knowledge
Evaluate Pilot Assembly Condition
Inspect all pilot light components
⚠️ Warning: Never use wire or drill bits to clean gas orifices - damage affects safety
Check for Draft and Ventilation Issues
Assess air movement affecting pilot
⚠️ Warning: Improper ventilation causes carbon monoxide accumulation
Test Gas Supply and Pressure
Verify adequate gas delivery
⚠️ Warning: Gas pressure testing requires licensed technician with proper tools
Professional Component Testing
Advanced diagnosis of control systems
⚠️ Warning: Gas control repairs require licensed professional for safety and code compliance
Pilot Light Repair Costs
🔧 DIY Attempt
⚠️ Risks:
- • Gas leaks if connections disturbed improperly
- • Carbon monoxide exposure from improper repairs
- • Fire hazard from gas accumulation
- • Damage to gas valve from incorrect procedures
- • Violation of local codes requiring licensed work
👷 Professional Service
✅ Includes:
- • Complete pilot system diagnosis
- • Thermocouple testing and replacement
- • Pilot assembly cleaning or replacement
- • Gas pressure verification
- • Draft and ventilation assessment
- • Safety system verification
Detailed Cost Breakdown
| Item/Service | Low | High |
|---|---|---|
| Service call and diagnosis | $125 | $200 |
| Thermocouple replacement | $150 | $250 |
| Pilot assembly cleaning | $150 | $200 |
| Pilot assembly replacement | $200 | $350 |
| Electronic ignition upgradeEliminates pilot light | $400 | $800 |
| Total Range | $1025 | $1800 |
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Prevention Tips
Annual Pilot Assembly Cleaning
Yearly cleaning prevents debris buildup that causes pilot outages. Remove spider webs, dust, and corrosion during fall startup service.
Protect from Wind and Drafts
Install wind guards or screens around heater. Ensure cabinet doors seal properly to prevent drafts from extinguishing pilot.
Regular Thermocouple Inspection
Check thermocouple position monthly during heating season. Tip must be in pilot flame for proper operation.
Maintain Proper Ventilation
Keep heater area vents clear of debris. Blocked ventilation causes pilot problems and dangerous carbon monoxide buildup.
Consider Electronic Ignition Upgrade
Replace standing pilot with electronic ignition system. Eliminates pilot light issues and saves gas year-round.
🏊 Pro Tip: Regular professional maintenance prevents 90% of pool problems.Get your maintenance quote today
This Issue Requires Professional Service
Pilot light problems involve gas safety and require proper diagnosis. Our certified technicians safely repair pilot systems, replace thermocouples, and can upgrade to reliable electronic ignition. Don't risk gas leaks or carbon monoxide.
Mention "pilot light failures" when calling for faster service
Related Pool Problems
Heater Won't Ignite
Often RelatedMain burner ignition failures after pilot issues
Heater Ignition Failure
Often RelatedComplete ignition system problems
Heater Gas Smell
Sometimes RelatedGas leaks can cause pilot problems
💡 Did You Know? Pool problems often occur together.pilot-light-wont-stay-lit can lead to or be caused by these related issues. Understanding the connections helps prevent future problems.