Watts 0559121 Valve

The Watts 0559121 (Series LFMMV-M1-US) is a professional-grade 1 inch union sweat mixing valve designed for precise temperature regulation in residential and commercial domestic water systems. Engineered with a lead-free cast copper silicon alloy body, this thermostatic mixing valve maintains stable discharge temperatures between 80°F and 120°F (27°C - 49°C). It utilizes a high-performance solid wax hydraulic principle thermostat to compensate for fluctuations in supply pressure and temperature, ensuring a consistent tempered water output with an accuracy of +/- 3°F.

This unit features a double throttling design that simultaneously manages hot and cold inlets to provide superior flow characteristics and a low pressure drop. For reliable field performance, the Watts LFMMVM1-US includes integral check valves and stainless steel inlet filter washers to prevent cross-flow between supply lines. The union solder connections allow for efficient installation and easy maintenance access. This valve is multi-listed to meet ASSE 1017, ASSE 1069, and ASSE 1070 standards, making it a versatile choice for point-of-source or point-of-use applications where lead-free compliance is required.

• Precise Temperature Control: Solid wax thermostat maintains mixed water temperature within +/- 3°F.
• Comprehensive Compliance: Triple listed under ASSE 1017, 1069, and 1070 for various plumbing configurations.
• Cross-Flow Protection: Built-in check valves and filter washers protect system integrity.
• High Flow Capacity: Supports flow rates from 0.5 GPM up to 13 GPM, suitable for multiple fixtures.
• Lead-Free Construction: Complies with low-lead regulations for potable water safety.

What is the maximum pressure rating for this valve?
The Watts 0559121 is rated for a maximum internal operating pressure of 150 psi (10.3 bar).

Can I use this mixing valve with PEX or CPVC piping?
While this specific model features 1 inch union sweat (solder) connections, specialized adapters can be utilized to transition to PEX or CPVC systems as required by the job site.

What is the required temperature differential for the hot water inlet?
For optimal performance, the hot water inlet should be at least 5°F above the set mixed outlet temperature, with a recommended inlet supply range of 120°F to 180°F.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.