Description
The McDonnell & Miller Model 63 (Part Number 142400) is a dependable, mechanically operated low water cut off designed to protect hot water and steam boilers from the hazards of low water conditions. When water drops below a safe operating level, the Model 63 automatically interrupts the burner circuit — and with its built-in auto reset function, it restores normal operation once proper water level is re-established, without requiring manual intervention.
Key Features
- Auto reset operation — automatically restores burner circuit when safe water level returns
- Suitable for both hot water and steam boiler applications
- Mechanical float-type design for reliable, long-term performance
- 1″ NPT connection for straightforward installation into standard boiler tappings
- 50 PSI maximum boiler pressure rating
- Trusted McDonnell & Miller engineering backed by Xylem
Specifications
- Model: 63
- Part Number: 142400
- Connection Size: 1″ NPT
- Maximum Boiler Pressure: 50 PSI
- Reset Type: Automatic
- Operation Type: Mechanical (float-based)
- Application: Hot water and steam boilers
- Brand: McDonnell & Miller (Xylem)
Why Choose the McDonnell & Miller 63?
The Model 63 is a go-to solution for boiler protection in residential and light commercial hydronic and steam heating systems. Its mechanical float mechanism operates independently of electrical sensing components, providing a straightforward and proven means of low water protection. The auto reset feature minimizes service calls and downtime, making it a practical choice for both new installations and replacement applications. Backed by the trusted McDonnell & Miller name — now part of the Xylem family — this low water cut off delivers the reliability that HVAC and plumbing professionals depend on.
