Lochinvar & A.O. Smith 100110811 Switch

The Lochinvar & A.O. Smith 100110811 Blocked Outlet Switch is a critical safety component designed for high-efficiency commercial water heaters and boilers, including the Cyclone BTH and Armor series. This OEM pressure switch functions as a normally closed (NC) SPST contact, engineered to monitor flue gas backpressure. If the exhaust venting becomes obstructed or the pressure rises above the calibrated set point, the switch opens, breaking the 24V control circuit to immediately initiate a safety lockout. This prevents hazardous combustion byproducts from entering the mechanical room.

As a direct replacement for legacy part numbers 9006007215, 100052309, and 194910, the 100110811 ensures seamless integration with the integrated control module. It is common in BTH-400 and BTH-500 models, where precise manifold pressure and venting integrity are paramount. When troubleshooting a "Blocked Exhaust" fault code, technicians should inspect the silicone sensing tubes and the exhaust vent connection elbow for obstructions before replacing the switch to restore optimal water heater performance.

• Direct OEM Compatibility: Engineered specifically for A.O. Smith, Lochinvar, and State commercial gas units to maintain listing compliance.
• Fail-Safe Protection: Utilizes normally closed contacts that open on a rise in pressure, ensuring the burner shuts down if venting is compromised.
• Rugged Construction: Built to withstand the high-temperature environment of an ultra-high efficiency combustion chamber.
• Simplified Service: Standard SPST configuration and standard spade terminals allow for fast field installation and testing using a digital manometer.

What causes a blocked outlet switch to trip?
Tripping is typically caused by physical obstructions in the vent piping, such as bird nests or ice buildup, or by exceeding the maximum equivalent vent length specified in the manual.

How do you test the 100110811 switch?
A technician should check for continuity across the terminals when the unit is off. If the switch is open without pressure applied, or if it fails to open at the specified WC (water column) rating during a simulated blockage test, it requires replacement.

Can I use a universal pressure switch instead?
No. These switches are factory-calibrated to specific pressure thresholds to ensure safety. Using a non-OEM or universal blocked outlet switch can lead to improper operation or failure to shut down during a hazardous blockage.

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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.