The Watts LFF115-74 THD B 20-175 LS 50-145 3 is a 3" lead-free globe-pattern pilot-operated pressure reducing control valve with NPT connections, with a pilot adjustable from 20 to 175 psi. It features a ductile iron body and a buna-n seat. Rated to 300 psi and up to 160°F. This model is certified lead-free for potable-water installations.
This 3 inch ACV is armed with ArmorTek®, a patented 3-part advanced epoxy coating system designed to limit both microbial induced (MIC) and exposed metal substrate corrosion. This pressure reducing control valve is designed to automatically reduce a fluctuating higher inlet pressure to a constant lower downstream pressure regardless of varying flow rates. The quick closing action of the valve limits the possibility of damaging high inlet pressure from passing through the valve to downstream piping. This Classic valve style has a globe body pattern with threaded end connections, pressure range of 20-175 psi, configured with inlet and outlet gauge ports, Buna elastomers, and limit switch. Flow requirements below the normal range of the main line valve are handled by a separate, low flow by-pass valve with 50-145 psi adjustment range. SentryPlus Alert® technology provides intelligent pressure monitoring and notifications using integrated sensors, and integrates with the Sensor Control Monitor to deliver maintenance alerts through BAS via RS-485 Modbus or the Nexa® platform over Wi-Fi.
Features
- Body construction with patented 3-part ArmorTek epoxy coating for advanced corrosion resistance
- Globe body pattern with threaded end connections
- Low-flow bypass range 50-145 psi
- Integrates with the Sensor Control Monitor to deliver maintenance alerts to BAS via RS-485 Modbus or the Nexa platform by Wi-Fi connectivity
- Inlet/outlet gauge ports, gauge not included
- Includes limit switch
Common Questions
- What pressure setpoint can this valve be adjusted to?
- The pilot on this valve is spring-ranged for 20–175 psi, so your target setpoint must fall inside that band. Watts builds the 115/116 platform with several pilot springs (2-30, 10-75, 20-175, 20-200 and 30-300 psi); ordering a setpoint outside 20–175 psi means a different pilot, not a field adjustment. The low-flow bypass regulator on this -74 model is separately adjustable over 50-145 psi.
- What does the "-74" low-flow bypass do?
- A large control valve cannot hold a stable outlet pressure at very low demand, so downstream pressure creeps up overnight. The -74 adds a small bypass regulator piped around the main valve that takes over at low flow and holds the setpoint, then hands back to the main valve as demand rises. It is the standard fix for night-time pressure creep on municipal and campus mains.
- What is the maximum working pressure?
- This unit is built as THD (NPT Threaded) and is rated to 300 psi. Threaded and grooved bodies on this platform carry a higher working pressure than 150# flanged bodies, so do not assume a flanged datasheet applies here.
- What fluid temperature can the Buna-N trim handle?
- This valve is built with Buna-N elastomers, good to about 160°F. Watts offers the same body with Buna-N (to 160°F), FKM/Viton (to 250°F) or EPDM (to 300°F) — pick the elastomer for your fluid temperature, not the body.
- Is this valve certified lead-free for potable water?
- Yes. The "LF" prefix denotes Watts lead-free construction, compliant with the weighted-average 0.25% lead requirement of the Safe Drinking Water Act (NSF/ANSI 372) for potable-water service.
Specifications
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Type: Pressure Regulator
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Size: 3"
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Inlet Size: 3"
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Outlet Size: 3"
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Connection: NPT
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Body Material: Ductile Iron
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Seat / Seal Material: Buna-N
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Max Pressure (psi): 300
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Operation: Pilot-Operated Diaphragm
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Port Style: Full
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Country of Origin: United States
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Warranty: 1 Year Limited
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MPN: LFF115-74 THD B 20-175 LS 50-145 3
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Temperature: up to 160°F
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Lead-Free: Yes
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Item Type: Valve
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Control Function: Pressure Reducing (Low-Flow Bypass)
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Valve Platform: Classic (F-Series)
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Body Pattern: Globe
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Pilot Adjustment Range (psi): 20-175
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Low-Flow Bypass Range (psi): 50-145
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End Connection / Pressure Class: THD (NPT Threaded)
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Configured Options: Low-Flow Bypass;Limit Switch;Strainer;Bypass
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Coating: ArmorTek 3-Part Epoxy
