McDonnell & Miller 194-A-7B Controller

The McDonnell & Miller 194-A-7B (Part Number 167100) is a heavy-duty combination low water cut-off and pump controller engineered for commercial and industrial steam boiler applications. Designed to handle a maximum pressure of 250 PSI, this unit integrates a high-performance potentiometer switch to provide a proportional 135-ohm signal, ensuring a constant water level is maintained regardless of varying steaming rates. As a veteran-grade float-operated controller, it utilizes magnetic repulsion to actuate switches, effectively eliminating the common failure points associated with traditional bellows. This specific 194-A configuration includes alternate tappings and a water column body with 1/2" NPT integral tappings for gauge glass and tri-cock sets, streamlining installation on high-pressure vessels. The automatic reset functionality ensures continuous operation, while the 1-1/4" NPT equalizing piping connections provide the structural stability required for rigorous boiler water level control. For technicians replacing older Series 194 units, this model offers unmatched reliability in secondary pump control and burner low water fuel cut-off protection.

• Enhanced Reliability: Utilizes a magnetic repulsion mechanism instead of bellows to prevent mechanical fatigue and leaks.
• Proportional Control: Includes a 7B potentiometer switch (0-135 ohm) for precise, modulated water level management.
• High Pressure Rated: Certified for steam boilers operating at 250 PSI max pressure.
• Versatile Piping: Features alternate tappings to accommodate various water column and gauge glass configurations.
• Boiler Protection: Acts as a primary or secondary low water cut-off to protect the heat exchanger from dry-firing.

What is the difference between the 194-A and the standard 194?
The 194-A model features alternate tappings on the water column body, providing additional 1/2" NPT ports for more flexible gauge glass and tri-cock positioning compared to the standard casting.

Can the 194-A-7B be used for both pump control and burner cut-off?
Yes, this is a dual-function combination controller. It manages the feed pump via the proportional signal and serves as a critical safety low water cut-off for the burner circuit.

Is this unit compatible with 120V or 240V systems?
The internal switches are rated for 345 VA at either 120 VAC or 240 VAC, making it compatible with standard industrial electrical configurations.

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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.