The McDonnell & Miller 63-M-HD Head Mechanism (Part Number 143200) is a heavy-duty replacement head mechanism designed for the Series 63 Low Water Cut-Off

The outlet pressure is set by turning the hand-wheel or adjusting knob on top of the valve

stable torque output

It is typically used in applications where specific sequencing or close-off forces are needed to manage system flow against varying line pressures

Siemens Building Technology 599-03072 Valve 318820-201 The McDonnell & Miller 63-M-HDFor mission critical flow control in hydronic or steam systems, the Siemens 599 03072 Valve provides the precision required by modern building automation standards. This 2 way normally closed globe valve is engineered with a high durability bronze body and stainless steel trim to resist wire drawing and erosion in high demand environments. Built for versatile application, it excels in hvac control valve tasks, providing a linear flow characteristic