Lochinvar & A.O. Smith 100108826 Pressure Switch

The Lochinvar & A.O. Smith 100108826 Pressure Switch is a critical safety component designed for precise draft monitoring in high-efficiency commercial water heaters and boilers. This SPDT (Single Pole Double Throw) pressure switch serves as a reliable interface for the control board, verifying that the inducer blower is pulling the correct static pressure before allowing the ignition sequence to proceed. Engineered as a genuine OEM replacement part, it is frequently utilized in 75-gallon power-vented units and Lochinvar Knight or Armor series appliances to prevent hazardous flue gas accumulation caused by vent blockages or mechanical failures.

Constructed for professional-grade durability, the 100108826 air pressure switch features a high-sensitivity diaphragm that reacts to minute pressure differentials. For technicians troubleshooting HVAC error codes like "APS Open" or "Air Pressure SW," this component is the direct solution for failed continuity tests. Its SPDT configuration allows the system to toggle electrical circuits between two outputs, ensuring the Smart Touch control module maintains a closed loop during the entire heating cycle. This part replaces older iterations, including 9002511005 and 184355-000, providing a seamless fit for restricted-clearance control boxes.

• OEM Compatibility: Precision-engineered for Lochinvar and A.O. Smith systems, ensuring exact set-point alignment without manual calibration.
• High-Sensitivity Monitoring: Detects vent obstructions, intake blockages, or inducer motor speed drops to prevent unsafe combustion.
• SPDT Versatility: Supports complex wiring configurations where both normally open and normally closed signals are required for system safety diagnostics.
• Direct Troubleshooting Solution: Resolves common short-cycling and ignition failure issues linked to faulty pressure sensing.

What are the symptoms of a failing 100108826 pressure switch?
Common signs include the inducer motor running continuously without the igniter glowing, or the control board displaying an air pressure switch fault. You should also check for water in the sensing tubes or cracks in the diaphragm housing.

Can I use this as a universal replacement?
No, this is a brand-specific OEM part. While it fits many 75-gallon power-vent models, you must verify the specific set-point and connection diameter required for your unit's model and serial number.

Does this switch require a manual reset?
Most 100108826 applications are automatic reset, meaning they will close once the pressure differential is restored; however, the appliance control board may require a manual reset to clear the stored fault code.

This item is not eligible for free shipping.

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.