A burner constantly lit on a water tank can lead to energy waste, overheating, and potential safety hazards; consider using a thermostat for efficiency.
Is your water heater’s burner constantly lit but failing to heat the water properly? This common issue can leave you with lukewarm showers and higher energy bills. Understanding why this happens and how to fix it can save you time and money.
Why Your Water Heater Burner Stays Constantly Lit
A properly functioning gas water heater should cycle its burner on and off to maintain the set temperature. When the burner stays lit continuously, it indicates a system malfunction. Here are the most common causes:
1. Faulty Thermostat
The thermostat regulates water temperature by controlling gas flow to the burner. If it fails, the burner may stay on constantly. Test it with a multimeter or consider replacement if it’s not responding properly.
2. Dirty or Clogged Burner Assembly
Debris in the gas tube or burner can prevent proper ignition and heat transfer. As noted in this case study, compressed air can often clear these obstructions.
3. Malfunctioning Thermocouple
The thermocouple senses pilot light presence. If dirty or faulty, it may incorrectly signal the gas valve to stay open. Clean it with fine sandpaper or replace if necessary.
4. Sediment Buildup in Tank
Mineral deposits at the tank bottom can insulate water from the heat source, causing the burner to work overtime. Regular flushing helps prevent this issue.
Step-by-Step Troubleshooting Guide
Check the Thermostat Setting
First, verify the thermostat isn’t set too high (120°F is recommended). Adjust if needed and monitor burner behavior.
Inspect the Burner Assembly
Turn off gas supply and examine the burner for:
- Clogs or debris in gas ports
- Proper flame pattern (should be blue with yellow tips)
- Signs of rust or corrosion
Test the Thermocouple
Follow these steps:
- Turn off gas supply
- Disconnect thermocouple from gas valve
- Use multimeter to test for proper voltage (typically 25-35 mV)
- Replace if readings are outside specifications
When to Call a Professional
While some issues can be DIY-fixed, consider professional help for:
- Gas valve replacements
- Persistent problems after troubleshooting
- Older units (10+ years) that may need replacement
For complex HVAC issues, our guide on essential HVAC tools shows what professionals use to diagnose such problems.
Preventive Maintenance Tips
Annual Flushing
Drain several gallons from the tank to remove sediment. This improves efficiency and extends unit life.
Regular Component Checks
Every 6 months, inspect:
- Pilot light flame (should be blue)
- Burner condition
- Ventilation system
Temperature Monitoring
Use a thermometer to verify water temperature matches thermostat setting. Significant differences indicate system issues.
Energy Efficiency Considerations
A constantly lit burner wastes energy. According to Energy.gov, water heating accounts for about 18% of home energy use. Proper maintenance can reduce this significantly.
For homes with advanced temperature control needs, explore smart temperature regulation devices that can optimize your entire heating system.
Signs You Need a New Water Heater
Consider replacement if you notice:
- Rust-colored water
- Leaks around the tank base
- Frequent repairs needed
- Age over 10 years
Modern units offer better efficiency and reliability. The constant burner operation in older models often indicates declining performance.
