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Manufacturer Resources
Product Specs
- Body Material:
- Iron
- Buy American Act Compliant:
- No
- Ean:
- 98268018943
- Inlet Connection Size:
- 3/4 IN
- Inlet Connection Type:
- Female Threaded
- Inlet Thread Type:
- NPT
- Lead Free:
- Not In Scope
- Maximum Temperature Fahrenheit:
- 250
- Maximum Working Pressure Psi:
- 56
- Outlet Connection Size:
- 1 IN
- Outlet Connection Type:
- Female Threaded
- Outlet Thread Type:
- NPT
- Part Number:
- 382456
- Pressure Range:
- 30 to 75 PSI
- Pressure Relief Setting Psi:
- 75
- Pressure Steam Discharge Capacity:
- 1,886,000 BTU per hour
- Protection Type:
- Pressure
- Series:
- 740
- Department:
- Plumbing
- Product Group:
- Plumbing
- Product Subgroup:
- Valves
- Product Type:
- Relief Valve
- Brand Name:
- Watts
Watts 740-075 3/4 – Frequently Asked Questions
1) What size pipe does the Watts 740-075 boiler relief valve thread into?
The inlet is 3/4 inch female NPT and the outlet is expanded to 1 inch female NPT. So you thread it onto a 3/4 inch male NPT boiler tapping, then run the discharge line in 1 inch pipe. Do not reduce the discharge back down to 3/4 inch, the larger outlet is there so relieved pressure vents without restriction.
2) At what pressure does the Watts 740-075 relief valve open?
It is factory set to open at 75 psi. That is a fixed setting, not field adjustable on this model. The 740 series covers settings from 30 to 75 psi, so 75 is the top of the range. If your boiler nameplate maximum allowable working pressure is below 75 psi, you need a lower-set valve from the series instead.
3) Can I use this Watts 740 valve on a hot water heating boiler running above 200 degrees F?
Yes, within limits. The 740-075 is rated to 250 degrees F maximum temperature, which covers normal hydronic supply temperatures. It is a pressure-only relief device, so it responds to pressure, not temperature. If you need combined temperature and pressure protection (a domestic water heater, for example), this is the wrong valve.
4) What is the relief capacity of the Watts 740-075 and will it cover my boiler?
Steam discharge capacity is 1,886,000 BTU per hour. Size by comparing that against your boiler's gross input or output rating as required by code: the valve capacity has to equal or exceed the boiler's rating. For most residential and light commercial hydronic boilers that figure is well above what is needed.
5) Is the Watts 740-075 relief valve lead free and suitable for potable water?
No. The 740-075 has an iron body and is classed as not in scope for lead free, meaning it is intended for closed hydronic heating systems, not potable water service. For a domestic water heater or any drinking water line, use a lead-free T and P relief valve instead.
6) Is the Watts 740-075 Buy American Act compliant for a government or institutional job?
No. The 740-075 3/4 is listed as not Buy American Act compliant, so it will not satisfy a BAA or domestic-sourcing clause on a federal or federally funded project. On private work that restriction does not apply.
7) What is the difference between the relief setting and the working pressure on this Watts valve?
Two different numbers that get confused on the order form. The 740-075 relieves at 75 psi, and its maximum working pressure is listed at 56 psi, which is the system pressure it is meant to sit at in normal operation. Your boiler fill pressure should stay well under the 75 psi opening point or the valve will weep.
How fast can I get the Watts 740-075 3/4 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 740-075 3/4 come with a warranty?
Absolutely. The Watts 740-075 3/4 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Watts 740-075 3/4?
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