Watts 0156734 Relief Valve

The Watts 0156734 is a commercial-grade 3/4" T&P relief valve engineered for critical temperature and pressure protection in high-capacity hot water supply tanks. Also identified by model number 40XL-Z2-150-3/4, this valve features a robust bronze body construction and is equipped with a 5-inch thermostat extension. It is specifically designed for installation directly into tank tappings or hot water outlets, ensuring precise monitoring of internal conditions. This model operates with a fixed 150 psi pressure relief setting and a 210°F temperature relief threshold, providing an essential safety mechanism for commercial water heaters and pressurized storage vessels.

Built for durability in demanding mechanical rooms, the Watts 40XL utilizes a unique thermo-bonded coated thermostat that resists mineral buildup, maintaining reset accuracy over long-term service. The non-mechanical seat-to-disc alignment ensures a positive seal after operation, while the inclusion of tamper-resistant bonnet screws prevents unauthorized field adjustments. For contractors and HVACR technicians, this automatic reseating relief valve meets ASME and CSA standards, making it a reliable choice for system compliance and hardware protection in pressurized hydronic environments.

• Enhanced Thermal Protection: The 5-inch extension probe allows for accurate sensing in the hot water stream, preventing dangerous localized overheating.
• Corrosion Resistance: Heavy-duty bronze body and stainless steel internal components withstand harsh water conditions and high-temperature cycles.
• Reliable Reseating: Features a non-mechanical alignment design that ensures the valve closes securely after a discharge event, reducing water waste.
• Standard Compliance: Fully ASME rated and CSA listed, ensuring the component meets strict safety codes for commercial installations.

• What is the difference between the 40L and 40XL models? The 40XL model features an extended thermostat probe (5 inches) for sensing in the hot water outlet, whereas the 40L uses a shorter probe for direct tank tapping.
• Is this valve suitable for potable water applications? This specific part number (0156734) is the standard bronze version; for jurisdictions requiring Lead-Free compliance, please verify the "LF" prefix version.
• Can the pressure setting be adjusted in the field? No, this valve is factory-set at 150 psi. The tamper-resistant bonnet screws are designed to prevent recalibration to ensure safety standards are maintained.

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.