Description
Product Overview
The Xylem-McDonnell & Miller 150S-HD is a replacement switch head mechanism designed for use with the 150S-HD combination low water cut-off and pump controller. Sold as the head mechanism only (Part Number 173003), this component features a snap-acting SPDT (Single-Pole, Double-Throw) switch that delivers reliable, precise switching action for boiler low water protection and pump control applications. It is an ideal service replacement for existing 150S-HD installations, restoring full control functionality without requiring complete assembly replacement.
Key Features
- Snap-acting SPDT switch mechanism for fast, positive switching response
- Designed as a direct replacement head for the 150S-HD combination low water cut-off and pump controller
- Head mechanism only — compatible with existing 150S-HD float body assemblies
- Part Number 173003 for easy cross-referencing and ordering
- McDonnell & Miller quality engineering, backed by Xylem’s trusted brand heritage
- Suitable for steam and hot water boiler protection systems
- Simplifies field service and reduces downtime with a straightforward head replacement
Application
The 150S-HD head mechanism is used in commercial and residential boiler systems where low water cut-off protection and pump control are required in a single unit. The snap-acting SPDT switch ensures dependable cut-off action when water levels drop below safe operating thresholds, protecting the boiler from dry-fire damage and controlling circulator pump operation.
Product Details
- Brand: Xylem-McDonnell & Miller
- Model: 150S-HD
- Part Number: 173003
- Switch Type: Snap-Acting SPDT (Single-Pole, Double-Throw)
- Component: Head Mechanism Only
- Function: Low Water Cut-Off / Pump Controller
