McDonnell & Miller 194-A Controller

The McDonnell & Miller 194-A is a heavy-duty combination low water cut-off and pump controller designed specifically for commercial and industrial steam boiler applications. Engineered for systems with a maximum steam pressure of 250 PSI, this unit features dual snap-acting SPDT switches to ensure precise boiler water level control and reliable low-water protection. The 194-A series is often selected by technicians for high-pressure environments where alternate tappings are required for specific piping configurations. Utilizing a bellows seal to prevent leakage and a rugged float mechanism, this controller provides high-torque switching to prevent short-cycling of the feed pump. By maintaining the NWL (Normal Water Level) and providing a secondary safety shut-off, the Part Number 166700 minimizes the risk of dry firing. Its robust construction makes it a standard choice for steam boiler safety controls in demanding mechanical rooms requiring high-pressure LWCO solutions.

• Dual Switch Functionality: Integrated SPDT switches independently manage automatic pump activation and low-water burner cutout.
• High-Pressure Rating: Rated for up to 250 PSI, making it compatible with high-pressure steam process boilers.
• Versatile Installation: Features alternate tappings to accommodate various 1-inch NPT piping requirements and water column configurations.
• Snap-Acting Contacts: Eliminate "chatter" and arcing, extending the service life of the electrical components in high-vibration environments.

Common Questions:

How do I configure the 194-A for manual reset?
The standard 194-A operates with automatic reset; however, manual reset functionality can be achieved by integrating a secondary manual reset relay into the burner circuit if required by local mechanical codes.

What is the advantage of the snap-acting switch in this model?
Unlike mercury switches, the snap-acting SPDT switches in this McDonnell & Miller controller provide a positive "make or break" contact, preventing the erratic burner signals often caused by boiler water surging or vibration.

Can this unit be used on water heating boilers?
The 194-A is specifically engineered for steam boilers. For hot water heating systems, a probe-type or specialized low water cut-off designed for water service should be utilized instead.

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.