Weil McLain 511-624-303 Pressure Switch

The Weil McLain 511-624-303 Pressure Switch is a critical safety component specifically designed for Weil McLain CGi series boilers, most notably the CGi-5 model. This SPST (Single Pole Single Throw) switch is factory-calibrated to a set point of 1.12" WC (Water Column), ensuring the inducer motor is moving sufficient combustion air before the ignition sequence initiates. Featuring a dual 1/4" barb connection, this OEM replacement part provides a precise interface between the combustion blower and the control board to prevent hazardous operation during venting blockages or motor failure. As a veteran-grade HVAC air pressure switch, it is built to withstand the high-temperature environments of a boiler cabinet while maintaining tight switching tolerances. When troubleshooting ignition failure or short-cycling in Weil McLain gas boilers, verifying the integrity of this switch's diaphragm is a standard diagnostic step for any field technician. This boiler replacement part ensures your hydronic system continues to operate within the manufacturer’s specified safety parameters.

• Precise Calibration: Fixed at 1.12" WC to match the exact static pressure requirements of the CGi-5 boiler combustion circuit.
• Robust SPST Logic: Provides a reliable normally-open circuit that closes only when proper draft is established, preventing boiler safety lockout.
• Universal Barb Interface: The dual 1/4" barb connection accommodates standard pressure tubing for quick integration into existing pneumatic lines.
• OEM Reliability: Genuine Weil McLain 511-624-303 part ensures physical and electrical compatibility without the drift associated with aftermarket alternatives.

How do I verify if the 511-624-303 pressure switch is failing?
Technicians should use a manometer to measure the actual draft produced by the inducer. If the draft exceeds 1.12" WC but the SPST switch terminals show no continuity, the internal diaphragm or electrical contacts have likely failed.

What causes a boiler pressure switch to trip frequently?
Beyond a mechanical failure of the switch itself, common causes include blockages in the flue pipe, a cracked 1/4" pressure tube, or moisture buildup within the sensing lines, all of which disrupt the pressure signal.

Is this switch compatible with other Weil McLain CGi models?
While the 511-624-303 is the specific OEM part for CGi-5 models, other sizes in the CGi series may require different WC ratings. Always check the rating stamped on your existing switch before installation.

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.