Lochinvar & A.O. Smith 100111020 Switch

As a seasoned technician, you know that a Lochinvar 100111020 switch is a critical safety component designed to verify the integrity of the combustion air path. This blocked inlet switch operates as a normally closed safety limit, specifically engineered to detect air intake obstructions in high-efficiency Lochinvar boilers and A.O. Smith water heaters. When the intake system faces constricted airflow due to debris or mechanical failure, the switch opens to break the 24V control circuit, preventing incomplete combustion and the dangerous accumulation of carbon monoxide. Replacing a faulty 100111020 pressure switch is essential for resolving common ignition failure codes and "Air Pressure SW" faults often seen on the Smart System control interface.

Key Benefits:

• Ensures precise HVAC safety switch operation by monitoring intake static pressure.
• Protects the heat exchanger from damage caused by poor air-to-fuel ratios.
• OEM compatibility ensures a direct fit for 100111020 blocked air switch replacements.
• Heavy-duty construction designed for the high-cycle demands of commercial and residential heating.

Common Questions:

What are the symptoms of a failed blocked inlet switch?
Usually, the inducer motor will run continuously, but the igniter will not glow, or the system will throw a specific air pressure fault code on the display.

How do I test the 100111020 switch?
With the power off, check for continuity across the terminals. Since this is a blocked inlet pressure switch, it should typically show continuity (closed) during normal standby if it is a vacuum-style safety, or change state once the inducer reaches the required set point.

Does this switch fix "Air Pressure SW" error codes?
Yes, if the intake pipes and reference hoses are clear of obstructions, a faulty switch is the primary cause for this open-circuit fault.

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.

100111020 is the cross for NS2-0530-00