The Watts LF100XL4-Z11 150-180 is a 3/4" lead-free temperature and pressure (T&P) relief valve for residential water heater service, factory set at 150 psi and 180°F. It is rated to 150 psi and up to 210°F. This model is certified lead-free for potable-water installations.
This 3/4 inch lead free temperature and pressure relief valve is designed to provide automatic temperature and pressure protection to hot water supply tanks and hot water heaters up to 105,000 BTU/hr. This two-in-one relief valve provides a proven and cost effective means to protect against excessive temperature and pressure emergency conditions. It features a lead free copper alloy body with NPT male inlet and NPT female outlet connections, a unique thermostat with special thermo-bonded coating with 4 inch extension and test lever. The temperature relief is 180 degrees F (82 degrees C) and the pressure relief is set at 150 psi (10.3 bar).
Features
- Lead free copper alloy body construction
- Unique thermostat with special thermo-bonded coating
- Pressure set at 150 psi (10.3 bar)
- ASME rated and CSA listed
Common Questions
- What pressure is this valve set to?
- It is factory set to relieve at 150 psi and 180°F. The setting is fixed and is not field-adjustable.
- Will it fit my water heater — what BTU input does it cover?
- This valve is rated for 105,000 BTU/hr on the CSA temperature-steam basis. Code requires the relief valve's discharge capacity to equal or exceed the input of the appliance it protects, so the number on your heater or boiler nameplate must be at or below that figure. Compare it against the input rating on the water heater's data plate.
- Is this ASME rated?
- Yes. It is ASME rated and carries the "HV" code symbol under ASME BPVC Section XIII (the section that replaced Section IV for overpressure protection), and it is National Board (NBBI) certified. It is also ANSI Z21.22 / CSA 4.4 approved, which is the listing water heater relief valves are required to carry. Inspectors look for that stamp on the valve body, and it is there.
- Can I use this on potable water?
- Yes. It is certified lead-free to NSF/ANSI 372, which is what plumbing codes require for any device in a drinking-water line.
- What thermostat length do I need?
- This valve has a 4" thermostat probe. The probe must reach into the top 6" of the tank's stored water to sense temperature, so it has to match the depth of your tapping — too short and the valve never sees the overheat it exists to catch. Watts builds this series in several probe lengths; measure before ordering.
- Does the discharge have to be piped?
- Yes. Codes require the outlet to be piped full-size to a safe point of discharge, terminating with an air gap and no valve, cap, or reducer anywhere in the line — a relief valve that cannot discharge freely is not protecting anything. The manual test lever should be operated at least annually to confirm the valve is not seized.
Specifications
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Type: Relief
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Size: 3/4"
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Inlet Size: 3/4"
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Outlet Size: 3/4"
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Connection: NPT
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Max Pressure (psi): 150
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Pack Quantity: 50
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Country of Origin: United States
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Warranty: 1 Year Limited
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MPN: LF100XL4-Z11 150-180
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Temperature: up to 210°F
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Certifications: ASME Section XIII (HV), NBBI, ANSI Z21.22, CSA 4.4
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Lead-Free: Yes
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Relief Type: Temperature & Pressure
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Factory Set Pressure (psi): 150
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Temperature Setting (°F): 180
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Discharge Capacity (BTU/hr): 105000
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BTU Rating Basis: CSA Temperature Steam
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ASME Code Rating: ASME Section XIII (HV)
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Application: Residential Water Heater
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Thermostat / Element Length (in.): 4
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Shank Length: Standard
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Connection Configuration: MNPT inlet x FNPT outlet
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Automatic Reseating: No
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Manual Test Lever: Yes
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Approved for Potable Water: Yes
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SentryPlus Alert Flood Sensor: No
