Watts 0342691 Relief Valve

The Watts 0342691 (Model 335M2) is a high-capacity boiler pressure relief valve engineered for hydronic heating systems and low-pressure steam applications. Featuring a 3/4" female NPT inlet and 3/4" female NPT outlet, this ASME Section IV rated safety valve is factory-set to 30 PSI, providing critical overpressure protection for residential and light commercial boilers. With a steam discharge capacity of 510,000 BTU/hr, it serves as the direct 0342691 replacement for discontinued model 0342670. Professionals value its all-bronze body construction and high-heat resisting silicone disc, which ensures a positive shut-off and prevents seat leakage even in high-temperature environments up to 250°F. The Watts 335M2 3/4 design includes a specialized non-stick Teflon-to-metal seating and a stainless steel spring for consistent mechanical performance. For technicians managing hydronic boiler maintenance, this 335 series valve offers a compact footprint ideal for tight OEM piping configurations without sacrificing discharge throughput.

• ASME Section IV Certified: Designed and tested to meet rigorous safety standards for pressure vessel protection.
• Enhanced Durability: Features a bronze body and stainless steel spring to resist corrosion and mineral buildup.
• High BTU Rating: Supports systems up to 510,000 BTU/hr, making it suitable for a wide range of boiler sizes.
• Reliable Seating: The silicone disc and non-stick Teflon-to-metal seat ensure tight closure after pressure relief cycles.
• Direct Upgrade: Seamlessly replaces the older 0342670 model with identical footprint and 30 PSI relief setting.

Is the Watts 0342691 compatible with my older 0342670 valve?
Yes, the 0342691 is the updated manufacturer replacement for the discontinued 0342670. It maintains the same 3/4" FxF connections and 30# pressure rating for direct drop-in compatibility.

What is the maximum temperature rating for this relief valve?
The Watts 335M2 series is rated for a maximum operating temperature of 250°F (121°C), making it suitable for standard hydronic heating and low-pressure steam systems.

Can I use this valve on a potable water heater?
No, this is an ASME boiler relief valve specifically designed for space heating boilers. Potable water heaters require T&P (Temperature and Pressure) relief valves, typically from the Watts 40 or 100 series.

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.