Lochinvar & A.O. Smith 100166256 Pressure Switch

The Lochinvar & A.O. Smith 100166256 Pressure Switch is a critical safety and operational component designed for high-performance hydronic systems and commercial water heaters. This SPDT Pressure Switch (Single Pole Double Throw) functions as a direct OEM replacement part for the now-obsolete PRS3406, PRS2406, and 100166157 models. Engineered with a precision 1/4" barb connection, it monitors system pressure within a 1-5 PSI range, ensuring the firing circuit only completes when safe operating conditions are met. This switch is specifically optimized for the Lochinvar EnergyRite pool heater series, including models ER152, ER202, ER252, ER302, and ER402. By utilizing a 1-pole configuration, it provides reliable switching logic to protect against low-flow or over-pressure scenarios. For contractors, installing this genuine Lochinvar water pressure switch ensures seamless HVAC part compatibility and prevents the nuisance tripping often associated with universal aftermarket alternatives in high-demand residential and commercial applications.

Key Benefits

• Exact OEM Specifications: Engineered as a direct fit for the PRS3406 pressure switch, eliminating the need for field modifications during replacement.
• Versatile SPDT Logic: The Single Pole Double Throw design allows for flexible wiring configurations to manage both safety shutdowns and status signaling.
• Broad Model Compatibility: Specifically calibrated for the Lochinvar EnergyRite line (ER152 through ER402) and compatible A.O. Smith water heaters.
• Safety Regulation: Actively monitors the 1-5 PSI pressure range to protect heat exchangers from damage caused by improper flow rates.
• Durable Construction: Built to withstand the thermal cycling and humidity levels common in boiler rooms and outdoor pool heater enclosures.

Common Questions

Is the 100166256 compatible with older PRS3406 units?
Yes, the 100166256 is the current manufacturer-designated replacement for the PRS3406 and PRS2406. It maintains the same form factor and electrical specifications for a drop-in installation.

What is the primary function of this switch in a pool heater?
This water pressure switch acts as a safety interlock. It ensures that the pump is circulating enough water through the heat exchanger before allowing the burners to ignite, preventing localized boiling and equipment failure.

Will this work with non-Lochinvar equipment?
While primarily designed for Lochinvar and A.O. Smith applications, it can be used in other systems requiring an SPDT pressure switch with a 1/4" barb and a 1-5 PSI trigger, provided the technical requirements match.

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.