To convert a propane water heater to natural gas, you need to replace the propane burner with a natural gas burner, adjust or replace the gas valve, and ensure proper venting and gas line connections, following manufacturer guidelines and local codes for safety compliance.
Converting a propane water heater to natural gas can save money on fuel costs while providing more consistent performance. However, this process requires careful attention to safety and proper procedures. This guide covers everything from compatibility checks to step-by-step conversion instructions.
Key Differences Between Propane and Natural Gas
Pressure Requirements
Natural gas operates at lower pressure (about 3.5″ WC) compared to propane (10-11″ WC). This requires adjusting the gas valve and replacing orifices.
Burner Characteristics
Propane burns hotter than natural gas (2,500 BTU/ft³ vs 1,000 BTU/ft³). The burner assembly may need modification to maintain proper combustion.
Ventilation Needs
While both fuels require proper venting, natural gas produces different combustion byproducts that may affect vent sizing. Learn about vent types.
Step-by-Step Conversion Process
1. Verify Compatibility
Check the manufacturer’s documentation. Many modern water heaters are convertible, but some older models may not be. Look for:
- Conversion kit availability
- Gas valve adjustment capability
- Burner compatibility
2. Gather Necessary Parts
You’ll typically need:
| Part | Purpose |
|---|---|
| Natural gas orifices | Smaller diameter for lower pressure gas |
| Conversion kit | Manufacturer-specific components |
| Pipe thread sealant | For gas line connections |
3. Shut Off Gas and Power
Turn off the gas supply at the main valve and disconnect power to the unit. This is critical for safety.
4. Replace Propane Components
Remove and replace:
- Propane regulator
- Burner orifices
- Gas valve (if not adjustable)
5. Adjust Air Shutter
Natural gas requires more primary air for proper combustion. Adjust the burner air shutter according to manufacturer specifications.
6. Check for Leaks
Use soapy water solution on all connections. Bubbles indicate leaks that must be fixed before operation.
7. Test Operation
Restore power and gas, then verify:
- Proper ignition
- Flame characteristics (should be blue with minimal yellow)
- No unusual odors
When to Call a Professional
Consider professional help if:
- Your unit isn’t certified for conversion
- You’re uncomfortable working with gas lines
- The burner requires significant modification
- You need to adjust venting requirements
According to energy.gov, improper conversions can reduce efficiency by 30% or create safety hazards.
Maintenance After Conversion
After converting to natural gas:
- Check flame color monthly (should be blue)
- Inspect venting annually
- Monitor for soot buildup
- Consider annual professional inspection
For related maintenance tips, see our guide on troubleshooting heater issues.
Cost Considerations
Conversion costs vary but typically include:
| Item | Cost Range |
|---|---|
| Conversion kit | $50-$150 |
| Professional installation | $200-$500 |
| Gas line modifications | $100-$300 |
According to AGA, natural gas typically costs 30-50% less than propane, making conversion cost-effective over time.
