Lochinvar & A.O. Smith 100111318 Intake Switch

The Lochinvar & A.O. Smith 100111318 Intake Switch is a critical safety component designed for commercial water heaters and high-efficiency boilers. This blocked intake air pressure switch operates as a normally closed (NC) contact, ensuring that the combustion blower only proceeds with the ignition sequence when the air inlet is clear of obstructions. As a veteran-grade OEM replacement part, it is engineered to detect vacuum fluctuations caused by restricted venting or excessive pipe runs. If technical diagnostics indicate an "Open Blocked Inlet" fault, this SPST pressure switch is the primary point of failure to inspect after verifying that the PVC air intake pipe and mesh screens are clear. This genuine Lochinvar 100111318 kit provides the exact activation pressure required for localized HVACR system performance, maintaining the precise pressure differentials needed for safe, continuous burner operation in demanding commercial environments.

• System Reliability: Prevents unsafe ignition cycles by monitoring combustion air supply integrity.
• Precise Calibration: Factory-set to specific inches of water column to match manufacturer vent length requirements.
• Broad Compatibility: Drop-in OEM replacement for various A.O. Smith Cyclone BTH and Lochinvar Knight models.
• Diagnostics: Facilitates rapid troubleshooting of blocked intake air pressure switch error codes and lockouts.

What causes a "Blocked Inlet" error on A.O. Smith or Lochinvar units?
This fault usually stems from physical obstructions in the intake venting, excessive pipe elbows, or a mechanical failure within the 100111318 switch itself. Always verify the intake screen and vent path before replacing the component.

How do I test the 100111318 pressure switch?
Using a multimeter set to continuity, a functional normally closed switch should show a closed circuit (0 Ohms) when the unit is off. If the meter shows "OL" without the blower running, the intake switch requires replacement.

Is this switch compatible with power direct vent models?
Yes, this part is specifically designed for power direct vent and ultra-high efficiency systems where independent monitoring of the air intake stream is mandatory for safety.

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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.