Weil McLain 511-624-404 Pressure Switch

The Weil McLain 511-624-404 Pressure Switch is a critical safety component engineered for CGS Series Boilers (Size 6), providing precise monitoring of combustion air and flue gas pressures. Operating with a 0.95" W.C. set point, this differential air pressure switch is calibrated for standard elevations from 0 to 1,999 feet. As an OEM replacement part, it ensures the boiler's induction blower provides sufficient airflow before allowing the ignition sequence to proceed, preventing hazardous operation under restricted venting conditions.

Designed for seamless integration into existing Weil McLain CGS boiler control circuits, this switch features heavy-duty diaphragm construction to withstand high-cycling environments common in residential and light commercial heating. Field technicians should verify the water column (W.C.) rating and elevation requirements during diagnostics, as using the incorrect boiler pressure switch can lead to intermittent "no heat" calls or ignition failure. This model replaces previous iterations, including those manufactured by Honeywell, and may require minor mounting adjustments depending on the original bracket configuration.

Key Benefits:

• Precision-calibrated 0.95 inch water column trip point for accurate CGS boiler safety shut-off.
• Compatible with Weil McLain CGS Size 6 units operating at standard altitudes (0-1,999').
• OEM technical specifications ensure reliable interface with 24V control systems and inducer assemblies.
• Durable housing prevents pressurized gas leakage and maintains set-point integrity over long-term use.

Common Questions:

How do I know if this pressure switch is failing?
Common signs include a flashing diagnostic light on the control board or the boiler inducer motor running without the burner igniting. Technicians should use a manometer to verify if the 0.95" W.C. threshold is being met at the sensing ports.

Can I use this switch for high-elevation installations?
No, the 511-624-404 is specifically rated for 0' to 1999'. For elevations above 2,000 feet, a different part number with a lower W.C. rating is required to compensate for lower air density.

Are the electrical connections directional?
While the electrical contacts are typically SPST (Single Pole Single Throw) and reversible for simple switching, the vacuum and pressure tubing ports must be connected correctly to the high and low sides as specified by the equipment manufacturer to ensure proper diaphragm movement.

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.