McDonnell & Miller 193-A Controller

The McDonnell & Miller 193-A is a heavy-duty combination low water cut-off and pump controller engineered for commercial steam boiler applications. Designed for boilers with a maximum pressure of 150 PSI, this unit features dual snap-acting SPDT switches for precise burner control and pump activation. The 193-A model utilizes alternate tappings to simplify installation on various boiler configurations. Its rugged float-operated mechanism ensures reliable level sensing even in turbulent conditions, preventing dry-fire scenarios that lead to catastrophic heat exchanger failure. For technicians managing high-pressure steam systems, the integral blow-down valve capability and manual reset compatibility make this 163500 replacement part a standard for maintaining operational safety and consistent water lines without frequent maintenance intervention.

Key Benefits

• Dual SPDT switches allow for simultaneous high-voltage pump control and burner interlocking.
• 150 PSI pressure rating meets the requirements for high-pressure industrial steam processes.
• Float-operated design provides mechanical reliability without the sensitivity issues of probe-type sensors in scaling water.
• Alternate tapping points offer flexibility when retrofitting legacy boiler trims or customized piping layouts.
• Snap-acting switches prevent arcing and ensure clean electrical engagement for extended contact life.

Common Questions

What is the difference between the 193 and the 93 series?
The 193-A features a broader body and specific alternate tapping configurations to accommodate larger water columns and different piping offsets compared to the standard 93 series.

Can this be used for both water leveling and safety shutdown?
Yes, the two switches allow the unit to function as a primary pump controller to maintain the water level and as a low water cut-off to shut down the burner if levels drop too low.

Is this unit compatible with high-pressure steam applications?
This specific model is rated for up to 150 PSI (10.5 kg/cm2), making it suitable for high-pressure commercial steam boilers rather than just low-pressure residential units.

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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.