The Belimo B2050VSS-15+LFX24-SR US pairs the B2050VSS-15 1/2" characterized control ball valve (VSS) with a factory-mounted fail-safe valve actuator. It delivers a Cv of 15 (about 30 GPM of water at a 4 psi drop, ASHRAE standard), 1000 psi close-off, and a 2000 psig WOG stainless steel body with an NPT female 1/2" connection, and is NSF/ANSI 61 (drinking water) and NSF/ANSI 372 (lead-free) certified for potable-water service. Equal-percentage flow gives precise, repeatable modulating control across the full stroke.
Specifications per the Belimo B2050VSS-15 product datasheet.
Overview
Belimo VS/VSS Series characterized control valves use a contoured ball and insert to linearize flow and hold valve authority for stable hydronic control. The B2050VSS-15 is a VSS stainless steel-body valve with an NPT female 1/2" connection, 2000 psig WOG body rating, 1000 psi close-off, and equal-percentage flow, shipped factory-assembled and tested with the LFX24-SR US actuator as a matched, ready-to-wire unit. The VSS variant steps up from the bronze VS to a <strong>stainless steel body rated 2000 psig WOG</strong> with a higher <strong>1000 psi close-off</strong>, and adds NSF/ANSI 61 (drinking water) and NSF/ANSI 372 (lead-free) certification for lead-free, potable-water service — built for higher-pressure and higher-spec applications.
Best for
- 1/2" 2-way chilled-water and hot-water control in fan-coil units, reheat coils, and zone hydronic loops
- Applications needing tight 1000 psi close-off and precise modulating control
- Higher-pressure or NSF-certified potable-water service (stainless, lead-free)
- Factory-assembled valve and actuator — no field coupling or mounting guesswork
Key Features
Characterized control
Equal-percentage ball and contoured insert linearize flow and hold valve authority for stable loop control.
2000 psig WOG · 1000 psi close-off
Stainless Steel body rated 2000 psig WOG with 1000 psi close-off (∆ps) and ANSI Class VI (bubble-tight) seat leakage.
Factory-assembled unit
Valve and actuator ship assembled and tested as a matched pair — no field coupling.
Fail-Safe actuator
Fail-Safe Valve Actuator, 24VAC/DC, Programmable (2-10VDC Default) Control.
Stainless steel, lead-free
Stainless steel body, ball, and stem rated 2000 psig WOG, NSF/ANSI 61 (drinking water) and NSF/ANSI 372 (lead-free) certified for potable-water and corrosive-media service.
Belimo reliability
316 stainless ball and stem with proven Belimo actuator drive for long service life.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Belimo |
| Assembly Part Number | B2050VSS-15+LFX24-SR US |
| Valve Model | B2050VSS-15 |
| Actuator Model | LFX24-SR US |
| Valve Type | Characterized Control Ball Valve (VSS) |
| Valve Size | 1/2" |
| Flow Pattern | 2-way |
| Cv (flow coefficient) | 15 |
| Nominal Flow (water) | 30 GPM at 4 psi ∆P (ASHRAE) |
| Body Pressure Rating | 2000 psig WOG (cold, non-shock) |
| Close-off Pressure ∆ps | 1000 psi |
| Leakage Rate | ANSI Class VI (bubble-tight) |
| Flow Characteristic | Equal percentage |
| End Connection | Internal thread, NPT (female) |
| Body Material | Stainless Steel steel (316) |
| Media | Chilled or hot water, up to 60% glycol |
| Actuator Type | Fail-Safe |
| Power Supply | 24VAC/DC |
| Control Signal | Modulating, MFT/Programmable |
| Certifications | NSF/ANSI 61, NSF/ANSI 372 (lead-free) |
| Approx. Assembly Weight | 3.7 lb |
Documentation
Belimo B2050VSS-15 Valve DatasheetRelated Products
Frequently Asked Questions
Does this valve come with the actuator attached?
Yes. The B2050VSS-15+LFX24-SR US ships as a factory-assembled, tested valve-and-actuator unit. The LFX24-SR US actuator is mounted and ready to wire.
What media can this valve handle?
Chilled or hot water and water with up to 60% glycol within the rated temperature range.
What is the close-off pressure?
1000 psi (∆ps) on water, giving dependable shutoff in VSS hydronic systems.
How many GPM will this valve flow?
With a Cv of 15, it passes about 30 GPM of water at a 4 psi pressure drop, the ASHRAE standard sizing point (GPM = Cv x square root of ∆P). At 1 psi it is about 15 GPM. Size to your actual design ∆P.
Is this a 2-way or 3-way valve?
This is a 2-way characterized control ball valve for modulating or two-position service depending on the actuator.
What is the difference between VS and VSS?
VS valves use a bronze body rated 600 psig WOG with 600 psi close-off for standard hydronic service. VSS valves use a stainless steel body rated 1500 psig WOG (2000 on the 1/2") with a higher 1000 psi close-off and add NSF/ANSI 61 and NSF/ANSI 372 (lead-free) certification for higher-pressure and potable-water applications. This is a VSS valve rated 2000 psig WOG / 1000 psi close-off.
- Pattern:
- 2-way
- Valve Size:
- 1/2 inch
- Cv:
- 15
- GPM:
- 30
- End Fitting:
- Internal thread
- Actuator Type:
- Fail-Safe
- Voltage AC/DC:
- 24 V
- Control Type:
- Modulating
- Control Type:
- MFT/Programmable
