Lochinvar & A.O. Smith 100109951 Pressure Switch

When you are troubleshooting a pressure switch failure on a high-efficiency hydronic system, the Lochinvar & A.O. Smith 100109951 is the specific OEM replacement part required to restore precise combustion air pressure monitoring. This air pressure switch is factory-calibrated for the BTN 200/366 series water heaters and boilers, ensuring that the blower is moving sufficient air for safe ignition. As a normally open (NO) switch with a set point of -2.40" WC, it acts as a critical safety interlock; if the vent produces insufficient draft or the intake becomes restricted, the contacts will not close, effectively locking out the burner to prevent hazardous operation.

The 100109951 pressure switch btn 200/366 is engineered for high-cycle reliability in commercial and residential heating environments. It integrates seamlessly with the existing HVAC control board, utilizing a standard spade terminal connection and flexible tubing ports for a fast, drop-in replacement. By maintaining the correct differential pressure range, this OEM Lochinvar replacement part prevents frequent "No Flame" errors and nuisance shutdowns caused by drifting tolerances found in aftermarket alternatives. For technicians, verifying the pressure switch setting against the unit's data plate is essential during any gas water heater repair to ensure local code compliance and peak thermal efficiency.

Key Benefits:

• OEM Compatibility: Specifically designed for A.O. Smith and Lochinvar BTN 200 and BTN 366 models, ensuring exact cut-in/cut-out values.
• Safety Interlock: Features a -2.40" WC set point to monitor induced draft fan performance and vent integrity.
• Durable Construction: Built to withstand the temperature fluctuations and moisture common in condensing HVAC systems.
• Easy Installation: Features a standardized mounting bracket and port configuration for rapid field replacement by contractors.

Common Questions:

• What causes a pressure switch stuck open error? This is usually due to a blocked flue, restricted air intake, or failing blower motor, though a ruptured diaphragm in the 100109951 may also be the cause.
• Can I use this switch for other Lochinvar models? No, you should always verify the part number against your specific model and serial number, as pressure switch settings vary significantly between BTN 200 and other boiler series.
• Does this kit include the pressure tubing? This is the pressure switch assembly; it is recommended to inspect and reuse existing silicone tubing or replace it if it shows signs of cracking or heat 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.