The Belimo B2050VS-04+LFX24-SR-S US pairs the B2050VS-04 1/2" characterized control ball valve (VS) with a factory-mounted fail-safe valve actuator. It delivers a Cv of 4 (about 8 GPM of water at a 4 psi drop, ASHRAE standard), 600 psi close-off, and a 600 psig WOG bronze body with an NPT female 1/2" connection. Equal-percentage flow gives precise, repeatable modulating control across the full stroke.
Specifications per the Belimo B2050VS-04 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 B2050VS-04 is a VS bronze-body valve with an NPT female 1/2" connection, 600 psig WOG body rating, 600 psi close-off, and equal-percentage flow, shipped factory-assembled and tested with the LFX24-SR-S US actuator as a matched, ready-to-wire unit. The VS is the bronze-body version rated <strong>600 psig WOG</strong> with <strong>600 psi close-off</strong> for standard chilled- and hot-water hydronic service. Where higher pressure or NSF-certified, lead-free potable-water service is required, the stainless <strong>VSS</strong> variant rated 1500 psig WOG / 1000 psi close-off is the step-up option.
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 600 psi close-off and precise modulating control
- Equal-percentage characterized flow for repeatable modulation and good valve authority
- 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.
600 psig WOG · 600 psi close-off
Bronze body rated 600 psig WOG with 600 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.
Bronze body, NPT
Durable bronze body rated 600 psig WOG with stainless ball and stem and NPT female threaded connections.
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 | B2050VS-04+LFX24-SR-S US |
| Valve Model | B2050VS-04 |
| Actuator Model | LFX24-SR-S US |
| Valve Type | Characterized Control Ball Valve (VS) |
| Valve Size | 1/2" |
| Flow Pattern | 2-way |
| Cv (flow coefficient) | 4 |
| Nominal Flow (water) | 8 GPM at 4 psi ∆P (ASHRAE) |
| Body Pressure Rating | 600 psig WOG (cold, non-shock) |
| Close-off Pressure ∆ps | 600 psi |
| Leakage Rate | ANSI Class VI (bubble-tight) |
| Flow Characteristic | Equal percentage |
| End Connection | Internal thread, NPT (female) |
| Body Material | Bronze (316 SS ball & stem) |
| Media | Chilled or hot water, up to 60% glycol |
| Actuator Type | Fail-Safe |
| Power Supply | 24VAC/DC |
| Control Signal | Modulating, MFT/Programmable |
| Approx. Assembly Weight | 3.7 lb |
Documentation
Belimo B2050VS-04 Valve DatasheetBelimo B2050VS-04+LFX24-SR-S US Assembly DatasheetBelimo VS/VSS Installation InstructionsRelated Products
Frequently Asked Questions
Does this valve come with the actuator attached?
Yes. The B2050VS-04+LFX24-SR-S US ships as a factory-assembled, tested valve-and-actuator unit. The LFX24-SR-S 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?
600 psi (∆ps) on water, giving dependable shutoff in VS hydronic systems.
How many GPM will this valve flow?
With a Cv of 4, it passes about 8 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 4 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 VS valve rated 600 psig WOG / 600 psi close-off.
- Pattern:
- 2-way
- Valve Size:
- 1/2 inch
- Cv:
- 4
- GPM:
- 8
- End Fitting:
- Internal thread
- Actuator Type:
- Fail-Safe
- Voltage AC/DC:
- 24 V
- Control Type:
- Modulating
- Control Type:
- MFT/Programmable