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Manufacturer Resources
Product Specs
- Application:
- Boiler
- Body Material:
- Iron
- Country Of Origin:
- United States
- Inlet Connection Size:
- 2 IN
- Inlet Connection Type:
- Female Threaded
- Inlet Thread Type:
- NPT
- Maximum Temperature:
- 250°F
- Maximum Working Pressure:
- 20
- Outlet Connection Size:
- 2 1/2 IN
- Outlet Connection Type:
- Female Threaded
- Outlet Thread Type:
- NPT
- Pressure Range:
- 30 to 75 PSI
- Pressure Relief Setting:
- 30 PSI
- Pressure Steam Discharge Capacity:
- 5,250,000 BTU per hour
- Protection Type:
- Pressure
- Series:
- 740
- Test Lever:
- Yes
- Department:
- Plumbing
- Product Group:
- Plumbing
- Product Subgroup:
- Valves
- Product Type:
- Relief Valve
Watts 384042 – Frequently Asked Questions
1) What size pipe does the Watts 740 Series 0384042 relief valve thread into?
The inlet is 2 inch female NPT and the outlet is 2-1/2 inch female NPT. That expanded outlet is intentional, not a mismatch: the discharge line is one size larger than the inlet so the valve can pass full capacity without back pressure. Run the drain piping in 2-1/2 inch and do not reduce it downstream.
2) At what pressure does the Watts 0384042 boiler relief valve pop off?
It is factory set to relieve at 30 psi, which is the standard setting for a residential or light commercial hot water heating boiler. The valve must be set above the system operating pressure but at or below the boiler's maximum allowable working pressure, so pair it with a boiler rated at least 30 psi MAWP.
3) Is this Watts relief valve suitable for a steam boiler or only hot water?
It is a pressure-only relief valve for boiler service, rated to 250 degrees F with a 30 psi setting. It protects against overpressure, not temperature, so it is not a combination temperature and pressure (T and P) valve for a water heater. For a domestic water heater you want a T and P valve instead.
4) Does the Watts 0384042 have a test lever for annual testing?
Yes, it comes with a manual test lever so maintenance staff can lift and flush the seat on the regular schedule without pulling the valve. That matters for MRO and facility crews documenting periodic boiler inspections.
5) What is the body made of on this 2 inch Watts boiler relief valve?
Cast iron body, made in the United States. Iron is the usual choice for closed-loop hydronic boiler service, where the water is treated and not potable. It is not intended for open potable water systems.
6) How hot can the system run with a Watts 740 Series 0384042 installed?
Maximum rated temperature is 250 degrees F, which covers standard hydronic heating loops. Mount the valve upright on the boiler tapping with no shutoff valve between the boiler and the relief valve, and pipe the 2-1/2 inch discharge to a safe point of termination.
How fast can I get the Watts 384042 delivered?
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Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit,
reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Watts 384042 come with a warranty?
Absolutely. The Watts 384042 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
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