Lochinvar & A.O. Smith 100277755 Pressure Switch

The Lochinvar & A.O. Smith 100277755 Pressure Switch is a mission-critical component engineered for precise atmospheric monitoring in high-efficiency boilers and water heaters. Calibrated to a .95" WC (Water Column) set point, this OEM replacement pressure switch ensures the inducer fan is generating the correct static pressure before allowing the ignition sequence to proceed. As a veteran-grade HVAC induction switch, it is designed to prevent unsafe operation caused by flue obstructions or mechanical blower failure, maintaining the strict safety parameters required by Lochinvar Knight and Armor series appliances.

Constructed for longevity in demanding mechanical rooms, this 0.95-inch WC air pressure switch features high-sensitivity diaphragms that respond to minute pressure differentials. For contractors performing a water heater pressure switch replacement, the 100277755 offers a direct-fit solution that eliminates the diagnostic headaches associated with generic "universal" parts. Integrating this specialized A.O. Smith combustion safety switch into your preventive maintenance routine ensures consistent burner performance and system reliability across compatible commercial and residential heating platforms.

• Factory-Calibrated Precision: Set specifically at .95" WC to match original engineering specifications for optimal combustion air verification.
• OEM Compatibility: Guaranteed fit for Lochinvar and A.O. Smith equipment, effectively replacing older part numbers and ensuring seamless integration with the existing Smart Touch control module.
• Enhanced Safety Logic: Functions as a vital fail-safe, preventing the gas valve from opening if the venting system or inducer motor fails to meet required pressure thresholds.
• Industrial-Grade Build: Engineered to withstand the thermal cycling and humidity common in high-recovery water heating environments.

What are the symptoms of a failing 100277755 pressure switch?
Common indicators include the inducer motor running continuously without ignition, or the control board throwing a "Pressure Switch Stuck Open" or "Stuck Closed" error code. Technicians should use a manometer to verify the draft pressure against the .95" WC rating before replacing.

Is this switch compatible with both Natural Gas and LP units?
Yes, this switch monitors air/flue pressure rather than gas pressure directly, making it suitable for both fuel types, provided the appliance requires a .95 inch WC set point for the inducer circuit.

Can I adjust the set point on this switch?
No. This is a fixed-calibration safety device. Attempting to manually adjust the pressure setting can lead to unsafe combustion conditions and equipment damage.

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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.