McDonnell & Miller 193-G Controller

The McDonnell & Miller 193-G serves as a heavy-duty combination low water cut-off and pump controller specifically designed for commercial steam boiler applications. Featuring two snap-acting SPDT switches, this unit provides precise mechanical control for both burner circuits and boiler feed pump activation. Built to withstand demanding mechanical environments, the 193-G is rated for a maximum steam pressure of 150 PSI. This model includes alternate tappings to facilitate versatile piping configurations in tight boiler rooms, allowing for direct mounting into the boiler's equalizing lines. The rugged float-operated mechanism ensures reliable liquid level monitoring, preventing dry-fire conditions that lead to catastrophic heat exchanger failure. By integrating the low water cut-off and pump control into a single casting, contractors can reduce installation time and minimize leak points compared to installing discrete components.

• Dual SPDT Snap Switches: Provides independent control for high-voltage burner shutdown and automatic water feeder activation.
• 150 PSI Maximum Pressure: Engineered for high-pressure steam systems requiring consistent water level control.
• Alternate Tappings: Simplifies field installation by offering multiple port options for equalizing pipe connections.
• Manual Reset Compatibility: Can be configured to meet strict local codes requiring manual intervention after a low-water event.
• Cast Iron Construction: Durable housing resists corrosion and thermal cycling stress common in industrial boiler environments.

Common Questions

What is the difference between the 193 and the 93 series controllers?
The 193 series, including the McDonnell & Miller 164760, features a larger float chamber and is specifically designed for boilers with high steaming rates or surging water lines where additional buoyancy and stability are required for accurate switching.

Can the 193-G be used for both lead and lag pump secondary control?
Yes, the snap-acting switches can be wired to signal a secondary pump controller or a high-level alarm, though its primary function is as a combination low water cut-off and primary feed control.

How do the alternate tappings benefit retrofitting older boilers?
The 193-G alternate tappings allow for flexible 1-inch NPT connections, making it easier to line up with existing sight glass or equalizing pipe heights without excessive repiping.

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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.