Xylem 64-HD Head Mechanism for Series Low Water Cut-Off - 64/764

The Xylem McDonnell & Miller 64-HD is a replacement head mechanism designed for use with Series 64 and 764 low water cut-off controls. This component provides reliable water level monitoring for both steam and hot water boilers in residential, commercial, and industrial applications.

Key Features:

• Complete head mechanism assembly including float and switches (float chamber sold separately)
• Features automatic reset mechanical low water cut-off with dual No. 2 switches
• Maximum operating pressure: 50 PSI (3.5 kg/cm²)
• Designed for screwed connection type for easy installation
• Allows quick replacement without disrupting existing piping—simply remove float chamber bolts and swap units
• Compatible with both steam and hot water boiler systems

McDonnell & Miller, a Xylem brand, is recognized for engineering comprehensive boiler controls and liquid level management solutions. The 64-HD head mechanism provides essential safety protection by shutting down the burner when water levels drop below safe operating levels. OEM part number 144400.