Watts 0559118 Valve Union Sweat

The Watts 0559118 LFMMV 3/4 Mix Union Sweat Valve is a lead-free thermostatic mixing valve designed for professionals requiring precise fluid control in residential and commercial domestic potable water systems. Built with a cast copper silicon alloy body, this valve utilizes a solid wax hydraulic principle thermostat to deliver a stable tempered water supply, even during significant pressure fluctuations. This unit is triple-certified to meet ASSE 1017, ASSE 1069, and ASSE 1070 standards, ensuring high-performance point-of-source or point-of-use temperature regulation. The double throttling design simultaneously manages both hot and cold inlets, maintaining an accuracy of +/- 3°F between 80°F and 120°F. As a direct replacement for LFMMVM1-US-3/4 and 0206001, it features 3/4-inch union sweat connections for rapid, leak-free integration. Integral check valves and filter washers prevent cross-flow and protect internal components from debris, while the adjustment cap with locking feature ensures setpoint stability in demanding high-flow environments up to 20 GPM.

• Triple Standard Compliance: Certified for ASSE 1017 (source), 1069 (single pipe), and 1070 (fixture) to cover any commercial application.
• Advanced Thermal Actuation: The high-response wax motor compensates for pressure changes to prevent thermal shock and scalding.
• Maintenance Efficiency: Features a union solder connection that allows the valve body to be removed for service without cutting existing copper pipe.
• System Protection: Built-in check valves eliminate the risk of hot water backing into cold lines, preventing common plumbing cross-connection issues.
• Secure Calibration: The tamper-resistant locking cap maintains the discharge temperature exactly where you set it during commissioning.

What is the minimum flow rate required for this valve to mix accurately?
This thermostatic mixing valve is engineered for low-flow sensitivity, maintaining accurate temperature control with a minimum flow rate of 0.5 GPM, making it suitable for high-efficiency fixtures.

Is the 0559118 model suitable for radiant heating applications?
While primarily designed for potable water tempering, the LFMMV series is commonly used in radiant systems to control supply temperatures; however, ensure the 80°F–120°F range matches your technical design requirements.

Does this valve protect against cross-flow in a multi-unit plumbing stack?
Yes, the Watts LFMMV-M1-US includes integral stainless steel check valves in both the hot and cold inlets to specifically block cross-migration and pressure imbalances.

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.