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Manufacturer Resources
Product Specs
- Body Material:
- Iron
- Buy American Act Compliant:
- No
- Ean:
- 98268019087
- Inlet Connection Size:
- 1 IN
- Inlet Connection Type:
- Female Threaded
- Inlet Thread Type:
- NPT
- Lead Free:
- Not In Scope
- Maximum Temperature Fahrenheit:
- 250
- Maximum Working Pressure Psi:
- 20
- Outlet Connection Size:
- 1 1/4 IN
- Outlet Connection Type:
- Female Threaded
- Outlet Thread Type:
- NPT
- Part Number:
- 382570
- Pressure Range:
- 30 to 75 PSI
- Pressure Relief Setting Psi:
- 30
- Pressure Steam Discharge Capacity:
- 1,300,000 BTU per hour
- Protection Type:
- Pressure
- Series:
- 740
- Department:
- Plumbing
- Product Group:
- Plumbing
- Product Subgroup:
- Valves
- Product Type:
- Relief Valve
- Brand Name:
- Watts
Watts 740-030 1 – Frequently Asked Questions
1) What size pipe does the Watts 740-030 boiler relief valve thread into?
The Watts 740 relief valve has a 1 inch female NPT inlet and a 1-1/4 inch female NPT outlet. That expanded outlet is intentional: the discharge line is a size larger than the inlet so it can pass full flow without restriction. You thread the inlet into a 1 inch tapping on the boiler and run 1-1/4 inch pipe off the outlet.
2) At what pressure does the Watts 740-030 relief valve open?
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 740 series itself covers 30 to 75 psi settings, so if your boiler nameplate calls for a higher maximum allowable working pressure you need the 740 ordered at that setting rather than this 30 psi version.
3) Can I use the Watts 740 on a steam boiler or only hot water?
The 740 is a pressure-only relief valve for boilers, rated to 250 F and carrying a steam discharge capacity of 1,300,000 BTU per hour. It protects against overpressure, not overtemperature, so it is not a temperature and pressure (T and P) valve for a domestic water heater. For a water heater you want a T and P valve instead.
4) How do I know the 740-030 is big enough for my boiler?
Size it by the boiler's gross output, not by the pipe size. This valve relieves 1,300,000 BTU per hour, so it covers any boiler whose rated input or output at the 30 psi setting falls at or under that figure. If your boiler plate exceeds that, you need a larger relief valve or a second one.
5) What is the Watts 740 relief valve body made of, and will it hold up on a hydronic system?
Iron body construction, rated to 250 F. Iron is standard for closed-loop hydronic boiler service where the water is not potable. Note the lead-free designation is listed as not in scope, so this is a heating valve rather than a potable water part.
6) Is the Watts 740-030 Buy American Act compliant for a government job?
No. The 740-030 1 is listed as not Buy American Act compliant, so on a federal or BAA-restricted project it will not qualify and you will need a domestically sourced relief valve instead.
7) What part number should I give my supplier for the 1 inch 30 psi Watts boiler relief valve?
Order it as Watts 740-030 1, series 740, manufacturer part number 382570. The trailing 1 in the model is the inlet size, and 030 is the 30 psi setting, so the same series ordered as a different number will come set at a different pressure.
How fast can I get the Watts 740-030 1 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 740-030 1 come with a warranty?
Absolutely. The Watts 740-030 1 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
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