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3/4 In Bronze Boiler Pressure Relief Valve, 40 psi, Threaded Female Connections
174A-040 3/4 - spec sheet
174A-040 3/4 - spec sheet
Manufacturer Resources
Product Specs
- Body Material:
- Bronze
- Buy American Act Compliant:
- USA
- Ean:
- 98268013078
- Inlet Connection Size:
- 3/4 IN
- Inlet Connection Type:
- Female Threaded
- Inlet Thread Type:
- NPT
- Lead Free:
- No
- Maximum Temperature Fahrenheit:
- 250
- Maximum Working Pressure Psi:
- 30
- Outlet Connection Size:
- 3/4 IN
- Outlet Connection Type:
- Female Threaded
- Outlet Thread Type:
- NPT
- Part Number:
- 274479
- Pressure Range:
- 30 to 150 PSI
- Pressure Relief Setting Psi:
- 40
- Pressure Steam Discharge Capacity:
- 800,000 BTU per hour
- Protection Type:
- Pressure
- Series:
- 174A
- Department:
- Plumbing
- Product Group:
- Plumbing
- Product Subgroup:
- Valves
- Product Type:
- Relief Valve
- Brand Name:
- Watts
Watts 174A-040 3/4 – Frequently Asked Questions
1) Will the Watts 174A-040 fit a 3/4 inch tapping on my boiler?
Yes. The 174A-040 has a 3/4 inch female NPT inlet and a 3/4 inch female NPT outlet, so it threads directly onto a 3/4 inch male NPT boiler tapping and takes a 3/4 inch male NPT drop pipe on the discharge side. Both ends are female, so you will need a nipple at the boiler if the tapping is female.
2) What pressure does the Watts 174A-040 relief valve open at, and can I adjust it?
It is factory set to relieve at 40 psi. That is a fixed set point built into the -040 model, not a field adjustment. The 174A series as a whole is built across a 30 to 150 psi range, so if your boiler needs a different relief point you order a different set-point model in the series rather than changing this one.
3) Is the Watts 174A-040 a pressure-only relief valve or does it also relieve temperature?
Pressure only. The 174A-040 protects against overpressure on a boiler and does not include a temperature probe element. If you are working on a water heater or a combination appliance that requires T and P protection, this is the wrong valve and you need a temperature and pressure relief valve instead.
4) Can I use the Watts 174A-040 on potable water or a domestic hot water heater?
No. The 174A-040 is not lead free, so keep it on closed-loop hydronic heating systems only. Anything touching potable water needs a lead free certified valve. This one is a bronze body boiler valve for the heating side.
5) Does the Watts 174A-040 meet Buy American requirements for a government or institutional job?
It is listed as Buy American Act compliant with USA origin, which is what a federal, school district, or municipal spec typically asks for on a boiler room submittal.
6) What part number do I order to replace a Watts 174A 40 psi 3/4 inch relief valve?
The model designation is 174A-040 3/4, carried under Watts part number 274479. The 040 is the 40 psi set point and the 3/4 is the NPT connection size, so both have to match what is on the boiler tapping and on the old valve's tag.
7) Is a bronze body worth it over a brass or cast relief valve on a boiler?
Bronze is the standard body material for a hydronic boiler relief valve because it holds up in hot circulating water without the dezincification risk you get from high-zinc alloys. The 174A-040 uses a bronze body rated to 250 degrees F, which covers normal hot water boiler operating temperatures.
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Does the Watts 174A-040 3/4 come with a warranty?
Absolutely. The Watts 174A-040 3/4 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
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