Xylem 339500 SA21-6 Float Valve Assembly for Series 21/221 Water Feeders

The Xylem 339500 Model SA21-6 is a complete float valve assembly designed for McDonnell & Miller Series 21 and 221 make-up water feeders used in boiler receiver tank applications. This genuine OEM replacement part ensures reliable, proportional water feed control to maintain optimal boiler water levels in commercial, industrial, and building applications.

Key Features:

• Complete valve assembly with integrated gaskets for Series 21 and 221 controls
• Soft-seat valve design provides long-lasting positive seal
• Float-operated proportional feed action for precise water level control
• Includes gaskets (items 2, 3, 4, and 6) for complete installation
• 3/4-inch NPT connection compatible with standard water supply lines
• Maximum water supply pressure rating of 150 PSI
• Maximum operating vessel pressure of 35 PSI
• Direct mounting design eliminates need for equalizing connections

Applications:

• Steam and hot water boiler systems
• Boiler receiver tank make-up water control
• Commercial and industrial HVAC applications
• Building automation and hydronic systems

This valve assembly is a critical component for maintaining safe and efficient boiler operation. McDonnell & Miller, a Xylem brand, is recognized as an industry leader in manufacturing boiler controls, liquid level controls, low-water cutoffs, and flow switches for demanding commercial and industrial environments.