Weil McLain 511-624-450 Switch

The Weil McLain 511-624-450 is a high-precision differential pressure switch engineered specifically for CGi model boilers (sizes 25, 3, and 4) and certain HE II boiler applications. This OEM replacement part is factory-calibrated to a 1.18" WC nominal set point, ensuring critical safety monitoring of the exhaust vent and combustion air system. With an operational differential range of 0.5 to 2.0" WC, it effectively prevents the boiler burner from firing unless proper ventilation and airflow are established, protecting the equipment from backdrafts and improper combustion. Designed for reliability at altitudes between 0 and 1,999 feet, the switch features a durable diaphragm and UL-approved construction capable of handling HVAC combustion systems up to 250 psi. In the field, technicians rely on this Tridelta FS6206A-2417 crossover to resolve frequent ignition failures or "soft lockouts" caused by inconsistent pressure signals, maintaining the high performance and energy efficiency of the heating plant.

• Precise 1.18" WC Actuation: Ensures the combustion blower provides sufficient draft before allowing gas valve activation.
• OEM Compatibility: Exact fit for Weil McLain CGi series helps eliminate field modification and troubleshooting time.
• Rugged Build: UL-approved for industrial environments and pressures up to 250 psi for long-term stability in HVAC systems.
• Combustion Safety: Acts as a primary safety interlock to monitor exhaust vent pressure and airflow integrity.

Is the 511-624-450 compatible with high-altitude installations?
This specific pressure switch is rated for 0 to 1,999 feet. For installations above 2,000 feet, always consult the Weil McLain service manual for the appropriate high-altitude part number, such as the 511-624-451.

What are the symptoms of a failing differential pressure switch?
Common indicators include the boiler inducer motor running continuously without the burner igniting, or the unit cycling on and off rapidly. Always check the silicone tubing for cracks or moisture buildup before assuming the switch is defective.

Can I use an aftermarket universal switch as a substitute?
Because the 1.18" WC set point is specific to the manufacturer's safety sequence, using a universal switch can lead to dangerous combustion conditions or persistent lockout codes. Always use genuine OEM part 511-624-450 for these models.

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.