Watts 0121591 Valve

The Watts 0121591 (Model LFN241X-5) is a heavy-duty, 1.25-inch lead-free automatic reseating temperature and pressure relief valve engineered for commercial hot water supply tanks and large-scale boilers. This technical 125# T&P valve is the modern lead-free replacement for the discontinued 0318820 (LFN241-5-125) and is designed to meet strict ANSI Z21.22 and CSA requirements. It features a rugged lead-free copper silicon alloy body and a 5-inch stainless steel extension thermostat. The valve is calibrated with a 125 PSI pressure setting and a 210°F temperature relief point, providing a massive 3,438,000 BTU/hr steam relief capacity. For modern building management, this unit often includes an integrated flood sensor with SentryPlus Alert technology to mitigate property damage from high-volume discharges.

• Maximum Discharge Capacity: Rated for up to 3,438,000 BTU/hr, providing critical protection for high-output commercial heating systems.
• Lead-Free Reliability: Constructed from lead-free copper silicon alloy to ensure full compliance with potable water regulations.
• Direct Retrofit Compatibility: Specifically replaces the older Watts 0318820 model with the same 1.25-inch M x 1-inch F NPT connections.
• Enhanced Thermal Response: The 5-inch stainless steel thermostat probe ensures accurate temperature sensing even in fast-cycling commercial environments.
• Automatic Reseating: Features non-mechanical seat-to-disc alignment and a test lever for straightforward maintenance and operational safety.

What is the difference between the 0121591 and the 0318820?
The 0121591 is the updated lead-free version of the 0318820. It maintains the 1-1/4" NPT inlet and 125 PSI setting but employs modern alloys to meet current plumbing codes.

Can I use this valve on a system rated for 150 PSI?
No. This specific model is a 125 PSI safety valve. Installing it in a 150 PSI system will cause premature discharge and potential system failure. Always verify the maximum allowable working pressure (MAWP) of your tank before selection.

Does this valve include the electronic monitoring kit?
While the valve features a built-in flood sensor, the activation kit for BMS or cellular alerts is sold separately. The physical valve operates mechanically regardless of sensor activation.

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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.