Lochinvar & A.O. Smith 100208242 On/Off Switch

The Lochinvar & A.O. Smith 100208242 On/Off Switch is a critical OEM replacement power switch engineered for high-efficiency hydronic and water heating systems. As a veteran-grade HVAC control component, this rocker-style switch features a clearly defined "I-O" symbol for definitive status verification during boiler troubleshooting and routine HVAC maintenance. Designed for 120V circuits, it serves as the primary manual disconnect on the control panel, bridging the gap between the external line voltage and the internal SMART SYSTEM control module.

This genuine Lochinvar part is built to withstand the thermal demands of commercial water heater environments. It is the direct replacement for units experiencing a "No Display" fault where incoming 120 VAC is present at the terminal strip but fails to pass through to the main board. Integrating this precise HVAC electrical switch ensures the integrity of the safety circuit and allows for localized power isolation without requiring a full breaker lockout during diagnostic procedures.

• Universal Compatibility: Fits a wide range of Lochinvar Knight (KH, KB), Crest, and Power-fin boilers, as well as A.O. Smith AWH and AWN series.
• Industrial Build Quality: High-cycle rated contacts prevent arcing and premature failure under inductive loads.
• Standardized Fitment: Snap-in design allows for rapid replacement in existing control panel assemblies without physical modification.
• Clear Status Indication: High-visibility I/O markings facilitate faster visual diagnostics for field technicians.

• How do I test if the 100208242 switch is failing? Use a multimeter to check for 120 VAC at the output terminals while the switch is in the "I" position. If input voltage is present but output is zero, the switch internal contacts are compromised.
• Is this switch compatible with older Knight fire tube boilers? Yes, this part is the standard OEM switch for Knight models ranging from KH 55 to KH 285, ensuring precise amperage handling for those control boards.
• Can I use a generic toggle switch instead? While many switches physically fit, OEM 100208242 is specifically rated for the environmental conditions and electrical load of these heating units, maintaining the UL listing of the equipment.

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.