Watts 0383308 Valve

The Watts 0383308 is a high-capacity ASME Section IV pressure relief valve designed specifically for hot water space heating boilers. Engineered as part of the Watts Series 740, this 1-1/4 inch NPT valve is factory set at 45 PSI and delivers a massive discharge capacity of 2,830,000 BTU/hr. Its iron body construction features expanded outlet drain connections (1-1/2 inch) to facilitate rapid pressure reduction during thermal expansion or runaway conditions.

This valve utilizes a non-mechanical seat-to-disc alignment that prevents sticking and freezing, while the high-temperature resisting water seal isolates the stainless steel spring from the media. The seat is strategically positioned above the drain to ensure sediment and water do not become trapped, which prevents fouling and ensures clean resets after operation. This boiler pressure relief valve is essential for maintaining system safety in commercial and residential hydronic heating applications where high BTU output is required.

• Ensures high-capacity pressure protection with a 2,830,000 BTU/hr rating.
• Prevents sediment buildup and seat fouling via a raised seat design.
• Constructed with a durable iron body and expanded 1-1/2" NPT outlet for superior flow.
• Features non-metallic disc-to-metal seating for reliable, drip-free seals.
• Protects internal components from corrosive water via an isolated spring chamber.

What is the difference between the Watts 0383308 and the 740-1 1/4-45?
These parts are identical. The numerical part number 0383308 corresponds to the 740 series model with a 1-1/4 inch inlet set at 45 PSI.

Can this valve be used for steam applications?
No, the Watts Series 740 is specifically designed for hot water heating boilers and should not be used in steam systems.

What size discharge pipe is required?
The discharge piping must match the 1-1/2 inch expanded outlet size of the valve to ensure the full BTU capacity can be safely vented without restriction.

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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.