The Xylem-McDonnell & Miller 94-HD is a heavy-duty combination low water cut off and pump controller engineered specifically for steam boiler applications. This head mechanism-only unit (Part Number 165300) delivers reliable, code-compliant protection by simultaneously monitoring boiler water level and controlling the feed pump — two critical functions in a single, proven device.
Key Features
- Combination low water cut off and pump controller in one compact unit
- Two snap-acting SPDT (Single-Pole Double-Throw) switches for independent cut off and pump control circuits
- Rated for steam boilers with a maximum pressure head of 250 PSI
- Head mechanism only — mounts to existing McDonnell & Miller float chamber or compatible body
- Part Number 165300 for easy cross-reference and ordering
- Rugged construction designed for the demanding environment of commercial and industrial steam systems
How It Works
The 94-HD uses a float-actuated mechanism to sense boiler water level. When the water level drops to the low-water threshold, the SPDT switches activate: one switch interrupts the burner circuit to prevent dry firing, while the second switch simultaneously energizes the feed pump to restore proper water level. This dual-action response protects the boiler from dangerous low-water conditions while automating water feed — reducing manual intervention and extending boiler life.
Application
- Commercial and industrial steam boilers
- Replacement head mechanism for existing 94-HD float bodies
- Systems requiring independent low water cut off and pump control switching
- High-pressure steam applications up to 250 PSI
Specifications
- Model: 94-HD
- Part Number: 165300
- Switch Type: Two snap-acting SPDT switches
- Maximum Pressure: 250 PSI
- Function: Combination low water cut off and pump controller
- Configuration: Head mechanism only
- Brand: Xylem-McDonnell & Miller
Why Choose McDonnell & Miller
McDonnell & Miller, a brand of Xylem, has been the industry standard in boiler low water cut off controls for over a century. The 94-HD continues that legacy with dependable snap-acting switch technology, straightforward installation, and robust performance in the harshest steam system environments.
