Watts 0121431 Valve

The Watts 0121431, also recognized as the LFLL40XL-150-1, is a high-capacity 1" T&P relief valve engineered for critical temperature and pressure protection in heavy-duty commercial hot water systems. This lead-free automatic reseating valve delivers a massive 2,134,000 BTU/hr relieving capacity, making it a standard choice for high-demand boilers and large-scale water storage tanks. Constructed with a durable lead-free copper silicon alloy body, it features a 1-21/32" extended shank designed specifically for tanks with thick insulation. The 3.5" thermo-bonded coated thermostat ensures precise thermal response at 210°F, while the set pressure of 150 PSI protects system integrity against over-pressurization. This unit is the direct updated replacement for legacy models 0163805 and LL40XL-1-150, integrating tamper-resistant bonnet screws and a non-mechanical seat-to-disc alignment for reliable, long-term field performance in commercial water heater applications.

Key Benefits

• High BTU Rating: Provides 2,134,000 BTU/hr steam discharge capacity to meet ASME and CSA certification standards for large commercial equipment.
• Extended Shank Design: The 1-21/32" shank simplifies T&P valve installation on modern high-efficiency tanks with extra-thick insulation layers.
• Lead-Free Compliance: Manufactured from lead-free alloy to meet stringent potable water safety regulations and federal mandates.
• Automatic Reseating: Features a test lever and automatic reseating capability to restore system protection immediately after a pressure or temperature event.
• Superior Thermal Protection: Utilizes a thermo-bonded coated probe for accurate temperature relief at 210°F (99°C).

Common Questions

Is the Watts 0121431 a direct replacement for the 0163805?
Yes, the 0121431 is the official lead-free updated version of the legacy 0163805 (LL40XL-150-1). It maintains the same 1" NPT connections and 150 PSI set point while upgrading to lead-free materials.

Does this valve include a flood sensor?
While this series is compatible with SentryPlus Alert technology, the standard 0121431 provides high-capacity mechanical relief. For active flood monitoring, ensure your system is compatible with Watts flood sensor connection kits.

What are the connection sizes for this relief valve?
This valve features a 1" MNPT inlet and a 1" FNPT outlet, ensuring it can handle the high-volume discharge required for commercial-grade heating systems.

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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.