McDonnell & Miller 194-B Controller

The McDonnell & Miller 194-B is a heavy-duty combination low water cut-off and pump controller designed for high-pressure steam boilers. Engineered for demanding industrial and commercial applications, this unit features a water column body with alternate tappings to facilitate precise integration with gauge glass and tri-cock installations. The 166701 controller utilizes a rugged magnetic repulsion mechanism, effectively eliminating the need for traditional bellows and reducing mechanical fatigue in high-heat environments. With a maximum pressure rating of 250 PSI and dual snap-acting SPDT switches, this controller ensures reliable burner shutdown and automated feed pump activation. The 1-1/4 inch NPT connections and specialized 3/4 inch NPT tappings provide the necessary versatility for steam boiler safety protocols and secondary water level management. This industrial-grade float-type water level control is built to withstand thermal cycling while maintaining consistent operational setpoints across all steaming capacities.

• Enhanced System Reliability: The magnetic repulsion design prevents the common failure points associated with bellows-style controllers in high-pressure steam environments.
• Versatile Application: Engineered with alternate tappings and a 250 PSI rating, making it compatible with a wide range of commercial and industrial steam vessels.
• Dual Switch Functionality: Two snap-acting SPDT switches provide independent control for the burner circuit and the boiler feed pump.
• Integrated Water Column: Simplifies installation by providing built-in ports for essential gauge glass and tri-cock maintenance.
• Precision Level Control: Maintains a consistent water line regardless of steaming rate, preventing dry-fire conditions and optimizing boiler efficiency.

What is the primary difference between the 194 and the 194-B model?
The 194-B (Part 166701) features alternate tappings specifically sized at 3/4 inch NPT for the gauge glass and tri-cocks, whereas standard models may use 1/2 inch ports. Always verify the existing piping dimensions to ensure a direct drop-in fit.

How often should a blow-down be performed on the Series 194?
For high-pressure boilers operating above 15 PSI, a daily blow-down is critical to clear sediment and prevent sludge from interfering with the float mechanism. Failure to perform routine blow-downs can lead to "sticky" float behavior or delayed low water response.

Can this unit be used for both pump control and low water safety?
Yes, the McDonnell & Miller 194-B acts as a combination controller. It is wired to cycle the feedwater pump while simultaneously serving as the primary or secondary low water cut-off (LWCO) for burner protection.

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.