McDonnell & Miller 193-B Controller

The McDonnell & Miller 193-B Controller is a heavy-duty, float-operated combination low water cut-off and pump controller specifically designed for commercial and industrial steam boiler applications. Engineered to handle a maximum pressure of 150 PSI, the 193-B model features a water column with alternate tappings to simplify integration with existing gauge glass and tri-cock sets. This unit utilizes two snap-acting SPDT switches (Number 5 switches) to provide reliable burner cut-off and feed pump activation, ensuring the boiler maintains a consistent water level without the need for complex bellows systems. The magnetic repulsion mechanism eliminates high-wear components, significantly reducing the risk of mechanical failure in high-pressure environments. Designed for 1-1/4 inch NPT equalizing piping, this steam boiler water level control provides the robust performance required for high-pressure steam systems where safety redundancy is non-negotiable. Whether you are performing a 163600 part replacement or a new install, the 193-B ensures your burner circuit is protected against catastrophic low-water conditions.

• Dual Switch Functionality: Features two snap-acting SPDT switches for independent control of the boiler feed pump and the burner safety circuit.
• Advanced Pressure Handling: Rated for 150 PSI steam boilers, making it suitable for both low and high-pressure industrial applications.
• Maintenance-Friendly Design: The magnetic repulsion technology replaces traditional bellows, reducing potential leak points and extending service life in harsh conditions.
• Versatile Piping Options: Provided with alternate tappings and a 1-1/4 inch NPT connection for flexible installation in various water column configurations.
• Integrated Water Column: Includes tappings for gauge glass and tri-cocks, centralizing boiler water level monitoring and safety controls in one robust casting.

What is the difference between the 193-B and standard 93 series controllers?
The 193-B is a water column style controller specifically designed with a larger body and 1-1/4 inch NPT tappings (compared to 1 inch on the standard 93 or 193-D) to match specific commercial steam boiler manifold requirements.

Can the switches be replaced without removing the entire controller?
Yes, the No. 5 snap-acting switch assemblies are modular and can be replaced or serviced by removing the head mechanism, allowing for faster field repairs by HVAC contractors.

How often should the 193-B be blown down?
For high-pressure boilers operating above 15 PSI, we recommend a daily blow-down. For systems under 15 PSI, a weekly blow-down is the minimum requirement to prevent sediment buildup from affecting the float-operated LWCO.

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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.