Lochinvar & A.O. Smith 100109958 Gas Valve

The Lochinvar & A.O. Smith 100109958 Gas Valve is a critical OEM replacement component designed for high-efficiency liquid propane (LP) water heaters and boilers. Engineered to operate on a 24V circuit, this valve is factory-calibrated to a 10" WC (Water Column) outlet pressure, ensuring precise fuel metering for optimal combustion stability. As a veteran-grade HVAC replacement part, it features a 3/4" NPT connection, providing the robust seal required for commercial and residential hydronic systems. This negative pressure gas valve is frequently utilized in Lochinvar Knight boilers and A.O. Smith high-end water heating units, where maintaining exact manifold pressure is non-negotiable for system safety and efficiency. Integrating this genuine OEM 100109958 valve prevents common ignition failures and "lockout" errors often associated with aftermarket alternatives. When troubleshooting LP gas heating systems, this component is the primary solution for resolving faulty solenoid engagement or inconsistent gas flow regulation.

Key Benefits for Contractors:

• Precise LP Regulation: Pre-set to 10" WC to ensure the burner receives steady liquid propane flow for clean combustion.
• OEM Compatibility: Exact drop-in replacement for A.O. Smith and Lochinvar units, eliminating field modification needs.
• Reliable 24V Signal Response: Optimized for smart control boards to prevent ignition failure error codes.
• Robust Build Quality: High-tolerance internal solenoids designed to withstand the high-cycle demands of modern boilers.

Common Questions:

Can I use the 100109958 valve for Natural Gas (NG) applications?
No. This specific model is calibrated for Propane (LP) at 10" WC. Using an LP valve for Natural Gas can lead to dangerous over-firing or component damage. Always verify your fuel source before installation.

What are the symptoms of a failing 100109958 gas valve?
Technicians typically see "Flame Failure" or "No Ignition" codes. Use a manometer to check if the valve is opening under 24V load; if you have voltage but no 10" WC pressure at the outlet, the internal solenoid has likely seized.

Is this a direct replacement for older Lochinvar gas valves?
Yes, the 100109958 replaces several legacy part numbers. Check your specific Lochinvar or A.O. Smith model and serial number to ensure the 3/4" port and electrical connections match your harness.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.