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3/4 In Lead Free Boiler Pressure Relief Valve, 125 psi, Threaded Female Connections
0121479 - spec sheet
0121479 - spec sheet
Manufacturer Resources
Product Specs
- Application:
- Boiler
- Body Material:
- Lead Free Copper Silicon Alloy
- Gpm When Relieved:
- Does Not Apply to Product
- Inlet Connection Size:
- 3/4 IN
- Inlet Connection Type:
- Female Threaded
- Inlet Thread Type:
- NPT
- Maximum Temperature:
- 250°F
- Maximum Temperature Fahrenheit:
- 250
- Maximum Working Pressure:
- 94
- Outlet Connection Size:
- 3/4 IN
- Outlet Connection Type:
- Female Threaded
- Outlet Thread Type:
- NPT
- Pressure Range:
- 50 to 150 PSI
- Pressure Relief Setting:
- 125 PSI
- Pressure Relief Setting Psi:
- 125
- Pressure Steam Discharge Capacity:
- 2,070,000 BTU per hour at 125 PSI
- Protection Type:
- Pressure
- Series:
- LF174A
- Shank Length:
- Does Not Apply To Product
- Temperature Steam Discharge Capacity:
- Does Not Apply to Product
- Test Lever:
- Yes
- Thermostat Material:
- Does Not Apply To Product
- Thermostat Probe Length:
- Does Not Apply To Product
- Department:
- Plumbing
- Product Group:
- Plumbing
- Product Subgroup:
- Valves
- Product Type:
- Relief Valve
Watts 121479 – Frequently Asked Questions
1) Will the Watts LF174A 0121479 relief valve thread into a 3/4 inch NPT tapping on my boiler?
Yes. The 0121479 has 3/4 inch female NPT on both the inlet and the outlet, so it threads onto a 3/4 inch male NPT nipple off the boiler tapping. Because the outlet is also female threaded, you pipe the discharge line out of it with 3/4 inch male NPT pipe rather than slipping it over a spud.
2) Is the Watts 0121479 a fixed 125 psi valve or can I adjust the relief setting?
It is a fixed-setting valve, factory set to relieve at 125 psi. The LF174A series spans 50 to 150 psi, but that range is covered by ordering the setting you need, not by adjusting this one in the field. If your boiler is rated for a lower maximum allowable working pressure, order the matching lower setting instead of this 125 psi unit.
3) What is the steam discharge capacity of the Watts 0121479 and how do I know it is big enough for my boiler?
The 0121479 relieves 2,070,000 BTU per hour at its 125 psi setting. Size by comparing that to the gross output of the boiler it protects: the valve's capacity has to equal or exceed the boiler's rated output. If your unit puts out more than 2,070,000 BTU/hr, you need a larger valve or additional relief capacity.
4) Does the Watts LF174A 0121479 protect against temperature as well as pressure?
Pressure only. There is no thermostat probe on this valve, so it reacts to pressure, not to water temperature. If you need combined temperature and pressure protection, such as on a water heater, a T and P relief valve with a thermostat element is the right part, not this one. The 0121479 is rated to 250 degrees F of service temperature.
5) Is the Watts 0121479 lead free and acceptable for potable water systems?
The body is a lead free copper silicon alloy, which is why it carries the LF prefix in the LF174A series designation. That makes it suitable where lead free components are required on potable or combined systems.
6) Does this Watts boiler relief valve come with a test lever for annual inspection?
Yes, the 0121479 has a test lever, so maintenance staff can manually lift and exercise the valve on the usual periodic check without pulling it from the piping. That matters for MRO and facility programs where relief valves get tested on a schedule.
7) What is the maximum operating temperature and working pressure of the Watts LF174A 0121479?
Service is rated to 250 degrees F with a 94 psi maximum working pressure, and the valve lifts at its 125 psi relief setting. Keep normal system operating pressure comfortably below the relief setting, otherwise the valve will weep and eventually fail to reseat.
How fast can I get the Watts 121479 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 121479 come with a warranty?
Absolutely. The Watts 121479 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
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