Lochinvar & A.O. Smith 100166156 Pressure Switch

The Lochinvar and A.O. Smith 100166156 Air Pressure Switch is a critical safety component designed for precise differential pressure sensing in high-efficiency water heaters and boilers. This switch, which is identical to PRS2405, monitors the venting system to ensure the combustion blower is moving sufficient air for safe operation before the ignition sequence begins. Built to handle low-positive or negative pressure fluctuations, it prevents short cycling and protects against blocked flue or intake obstructions. Veteran technicians recognize this part for its consistent set point reliability and high-temperature housing, making it a drop-in replacement for commercial water heater maintenance and boiler repair. This OEM pressure switch ensures the inducer motor maintains sufficient vacuum, confirming the integrity of the heat exchanger airflow during the entire heating cycle.

Key Benefits

• Direct OEM Matching: Replaces Lochinvar 100166156 and PRS2405 without the need for mounting modifications.
• Enhanced Safety: Precisely monitors air proving to prevent hazardous operation under poor venting conditions.
• Industrial Durability: Engineered to withstand the thermal cycles typical of condensing boilers and high-efficiency commercial water heaters.
• Quick Installation: Features standard electrical terminals and hose connections for rapid field replacement.
• Wide Compatibility: Integrated into various A.O. Smith and Lochinvar platforms, ensuring accurate combustion air pressure monitoring.

Common Questions

Is the 100166156 compatible with my specific Lochinvar boiler?
This switch is commonly utilized in the Lochinvar Knight and Armor series, but you should verify the pressure set point on your existing part’s label against the PRS2405 specifications to ensure a perfect match for your inducer assembly.

What causes this switch to trip frequently?
A tripped switch usually indicates a blocked vent, moisture in the tubing, or a failing blower motor. If the mechanical venting is clear, the internal diaphragm of the differential pressure switch may be compromised.

Can I use an adjustable universal switch instead?
Using an OEM replacement is highly recommended over universal parts to maintain the precise safety lockout parameters defined by the manufacturer for specific BTU inputs.

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.