Lochinvar & A.O. Smith 100166235 Pressure Switch

The Lochinvar & A.O. Smith 100166235 Pressure Switch is a critical safety component designed for precise draft proving in high-efficiency HVAC systems. This SPDT (Single Pole Double Throw) switch is factory-set to a .95" WC (water column) setpoint, ensuring that the inducer motor establishes the correct static pressure before the ignition sequence begins. As a direct replacement part, this unit is physically and functionally identical to PRS30015, featuring the exact mounting footprint and terminal configuration required for Lochinvar boilers and A.O. Smith water heaters. Engineers and technicians rely on this OEM pressure switch to prevent system operation during venting obstructions or inducer motor failure. Built for high-cycle reliability in commercial and residential applications, it maintains the precise differential pressure tolerances necessary to avoid nuisance lockouts while protecting the heat exchanger from improper combustion conditions.

Key Benefits:

• Exact OEM Compatibility: Verified as a drop-in replacement for PRS30015, ensuring seamless integration with existing wiring harnesses.
• Precise .95" WC Calibration: Fixed setpoint prevents ignition failure caused by inaccurate draft readings in condensing units.
• Versatile SPDT Logic: Single Pole Double Throw configuration allows for flexible normally open or normally closed circuit integration.
• System Protection: Acts as a primary safety limit to detect venting restrictions or blocked flue conditions instantly.
• Industrial-Grade Build: Designed to withstand the moisture and temperature fluctuations common in high-efficiency water heaters.

Common Questions:

How do I troubleshoot a 100166235 pressure switch error?
Verify that the pressure tubing is clear of condensation and cracks. Use a digital manometer to ensure the inducer motor is pulling at least .95" WC. If the draft is sufficient but the switch fails to close the circuit, the internal diaphragm or contacts may be faulty.

Can I use this to replace other pressure switches with different WC ratings?
No. Pressure switches must match the manufacturer’s specific water column rating. Installing a switch with a different setpoint can lead to dangerous combustion levels or persistent system lockouts.

What causes this switch to fail prematurely?
Common culprits include moisture buildup in the silicone tubing, heat stress from improper venting, or debris entering the sensing port. Always check the flue termination for obstructions during replacement.

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.