McDonnell & Miller 63-M-HD Manual Reset Low Water Cut Off, 50 PSI, SKU 63-M-HD

Description

Overview

The McDonnell & Miller 63-M-HD (Part Number 143200) is a manual reset mechanical low water cut off designed to protect hot water and steam boilers from the hazards of low water conditions. Supplied as the head mechanism only, this unit is an ideal replacement or upgrade component for existing installations, delivering reliable boiler protection without the need to replace the entire assembly.

How It Works

The 63-M-HD uses a proven mechanical float-based design to continuously monitor boiler water levels. When water drops below a safe operating threshold, the cut off automatically shuts down the burner to prevent dry-fire damage. The manual reset feature ensures that an operator must intentionally restore operation after a low water event, adding an important layer of safety accountability to any boiler room.

Key Features

• Manual reset operation — requires deliberate operator action to restore burner function after a low water trip
• Mechanical float design — dependable, time-tested low water detection technology
• Compatible with both hot water and steam boiler systems
• Maximum boiler pressure rating of 50 PSI
• Head mechanism only — designed for use with existing McDonnell & Miller bodies and piping configurations
• Part Number 143200 for easy cross-referencing and ordering
• Manufactured by McDonnell & Miller, an Xylem brand — a trusted name in boiler protection controls

Specifications

• Model: 63-M-HD
• Part Number: 143200
• Type: Manual Reset Mechanical Low Water Cut Off
• Application: Hot Water and Steam Boilers
• Maximum Boiler Pressure: 50 PSI
• Supply Includes: Head Mechanism Only
• Brand: McDonnell & Miller (Xylem)

Application

The 63-M-HD is suited for commercial and residential boiler systems where a manual reset low water cut off is required by code or desired for enhanced safety. Its head-only configuration makes it a cost-effective solution for service technicians replacing worn or failed head mechanisms while retaining existing piping and body hardware.