McDonnell & Miller 750B-C-4 Control

The McDonnell & Miller 750B-C-4 (Part Number 176317) is a rugged, cast iron body remote sensor chamber engineered for high-demand liquid level control in commercial and industrial boiler systems. Designed for seamless integration with Series 750B remote mount control modules, it features sight glass tappings and gage cock tappings to simplify visual monitoring and maintenance in the field. This model is equipped with a NEMA 4X enclosure, providing superior protection against corrosion and environmental ingress, making it suitable for harsh mechanical room conditions. Utilizing conductance actuated technology with four stainless steel probes, this unit supports complex multi-level functions including low water cut-off, pump on/off sequencing, and high-level alarm configurations. With a maximum steam pressure of 250 psig, it ensures reliable performance and safety redundancy for high-pressure vessels. Professional installation in series with existing limit and operating controls is required to maintain system integrity and CSD-1 code compliance.

• Multi-Probe Versatility: Four-probe configuration allows for simultaneous control of low water cut-off and differential pump levels.
• Industrial Durability: The cast iron chamber and NEMA 4X enclosure withstand high-pressure steam environments up to 250 psi.
• Simplified Maintenance: Integrated tappings for gage cocks and sight glasses permit quick diagnostic checks without de-pressurizing the system.
• Broad Compatibility: Fully compatible with Series 750B modules for both steam and hot water applications.

Can the probes be adjusted in the field?

Yes, any of the four stainless steel probes can be cut to length during installation to meet specific tank or boiler level requirements.

What type of wiring is recommended for the remote sensor?

For distances up to 500 feet, use #14 or #16 AWG MTW or THHN wire, ensuring probe runs are kept separate from high-voltage conduit.

Is this unit suitable for outdoor installations?

The NEMA 4X enclosure is rated for protection against hosedown and corrosion, though additional shielding is recommended for extreme exposure.

This item is not eligible for free shipping.

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.