To convert a natural gas water heater to propane, replace the gas valve, adjust the burner orifice, and ensure proper ventilation and safety measures are followed.
Converting a natural gas water heater to propane requires careful adjustments to ensure safe operation. While some manufacturers prohibit this conversion, proper techniques exist when performed by qualified professionals.
Key Differences Between Natural Gas and Propane
Natural gas and propane have distinct characteristics that affect water heater operation:
| Factor | Natural Gas | Propane |
|---|---|---|
| Pressure | 7″ water column | 11″ water column |
| Orifice Size | Larger | Smaller |
| Energy Content | 1,000 BTU/cu.ft. | 2,500 BTU/cu.ft. |
Conversion Process Step-by-Step
1. Verify Manufacturer Approval
Check if your water heater model allows conversions. As noted in A.O. Smith’s bulletin, some manufacturers only permit propane-to-natural gas conversions.
2. Obtain Conversion Kit
Purchase the manufacturer-approved conversion kit containing:
- Propane-specific burner orifice
- Gas valve adjustment tools
- Updated rating plate
3. Adjust Gas Valve Settings
Propane requires different pressure settings than natural gas. The gas valve must be reconfigured to deliver proper fuel flow.
4. Replace Burner Orifice
The smaller propane orifice restricts flow to match propane’s higher energy content. This prevents dangerous over-firing.
5. Verify Venting Requirements
Propane combustion produces different exhaust characteristics. Ensure your venting system meets current gas appliance venting standards.
Safety Considerations
Professional Installation Required
Gas conversions should only be performed by licensed technicians. Improper adjustments can create fire hazards or carbon monoxide risks.
Post-Conversion Testing
After conversion, technicians should:
- Check for gas leaks
- Verify proper burner ignition
- Measure combustion efficiency
- Confirm safe exhaust venting
Alternative Solutions
Dual-Fuel Systems
Consider installing a separate propane water heater in parallel with your natural gas unit. This provides fuel flexibility without conversion risks.
Tankless Options
Propane tankless water heaters offer excellent efficiency and may be more cost-effective than converting an existing natural gas tank.
Manufacturer Warnings
Many manufacturers void warranties if unauthorized conversions are performed. Always consult your water heater’s documentation before attempting any modifications.
