McDonnell & Miller 750B-C-3 Control

The McDonnell & Miller 750B-C-3 is a robust cast iron liquid level control chamber designed as the modernized, high-performance successor to the legacy 750-C-3 model. Engineered for demanding industrial and commercial HVAC systems, this remote mount sensor chamber (Part Number 176316) serves as a critical component in boiler water level management. Utilizing an electrode-based conductance system, it is configured for use with 3 stainless steel probes to provide precise pump control and low water cut-off functionality. The unit features built-in sight glass tappings and gage cock tappings for direct visual monitoring, integrated into a rugged NEMA 4X enclosure that provides superior protection against corrosion and environmental ingress. Rated for high-pressure operations up to 250 psig, this control ensures reliable performance in steam or hot water applications. When paired with a 750B series control module, it delivers a precise interface for secondary low water cut-off (LWCO) safety circuits, maintaining CSD-1 code compliance while facilitating professional-grade field maintenance through its dual-valve blow-down compatibility.

Key Benefits:

• Industrial Grade Durability: Heavy-duty cast iron body construction withstands rigorous temperature cycling and high-pressure steam environments.
• Advanced Environmental Protection: The NEMA 4X electrical enclosure guarantees moisture and corrosion resistance, essential for mechanical room longevity.
• Precision Level Monitoring: Integrated sight glass and gage cock tappings allow for immediate manual verification of water levels.
• System Versatility: Designed to facilitate pump control, high-level alarms, and low water safety shut-off when configured with the appropriate probe lengths.
• Direct Legacy Replacement: Seamlessly replaces the previous 750-C-3 control, utilizing the same footprint for easier field upgrades.

Common Questions:

Does this unit come with the probe rods included?
The 176316 chamber is the housing and sensor head assembly. Probe rods are typically specified and ordered separately based on the required insertion depth for your specific vessel or boiler requirements.

Can this be used for primary low water cut-off?
Yes, the McDonnell & Miller 750B-C-3 is frequently used as a primary or secondary conductance level control in systems requiring remote mounting from the boiler shell.

What is the maximum pressure rating for this chamber?
This cast iron remote mount control is engineered for a maximum steam pressure of 250 psig.

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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.