Lochinvar & A.O. Smith 100109916 Limit Control

The Lochinvar & A.O. Smith 100109916 Dual Limit Control is a critical safety component designed for heavy-duty commercial and residential heating systems. This OEM water heater part serves as a high-precision manual reset limit switch, engineered to prevent hazardous overheating by interrupting the burner circuit when temperatures exceed the safe operational threshold. As a direct 100109916 replacement for legacy models 11B79-3, 9004529005, and 192828, this dual-control unit provides reliable HVAC temperature regulation with an adjustable range of 120°F to 180°F and a fixed 205°F high-limit trip point. The 3/4-inch tank opening ensures a secure fit for standard commercial water heater configurations. For technicians troubleshooting pilot light failure or water heater lockout, this genuine A.O. Smith limit control offers the mechanical reliability required to maintain system uptime and meet strict safety codes without the inconsistencies often found in aftermarket alternatives.

• Direct OEM Compatibility: Seamlessly replaces obsolete part numbers 11B79-3 and 9004529005 for Lochinvar and A.O. Smith units.
• Dual Control Safety: Integrates both temperature regulation and a fail-safe high limit switch in a single, robust housing.
• Manual Reset Function: Hard-trip protection at 205°F requires professional inspection before system restart, ensuring underlying faults are addressed.
• Field-Proven Reliability: Built for commercial environments, providing consistent thermal protection in high-demand heating applications.
• Precision Setting: Features a 4°F differential and adjustable 120-180°F range for exact aquastat control.

What causes the 100109916 limit control to trip?
The most common causes for a limit switch lockout include excessive scale buildup on the sensing bulb, a malfunctioning gas valve, or restricted water flow causing localized overheating within the tank.

Can I use this to replace a single-function limit switch?
This dual limit control is designed specifically for systems requiring both operational control and high-limit safety. Check your wiring diagram to ensure the 120V or millivolt circuit is compatible with dual-lead configurations.

Is the 100109916 compatible with 9004529005?
Yes, the 100109916 is the designated manufacturer-updated version and is fully compatible with units previously utilizing the 9004529005 or 11B79-3 controls.

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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.