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Single-Duct VAV Terminals | YFVAV-S-T100 | YONGFAN
122–6,232 m³/h · Pressure-Independent · Modbus / BACnet

Single-Duct VAV Terminals: YFVAV-S-T100 Series

A VAV terminal must hold zone airflow across changing duct pressure while staying inside the required minimum, maximum, acoustic and reheat limits.

YONGFAN’s YFVAV-S-T100 Single-Duct VAV Terminal Family covers nine precision inlet sizes from Ø125 to Ø400 mm spanning 122 to 6,232 m³/h. Features multi-point cross-averaging airflow sensing, pressure-independent DDC actuator integration, optional 1-row/2-row hot-water reheat coils (1.6–34.6 kW), and 914 mm acoustic attenuator sections.

Flow Range122–6,232 m³/h
Inlet RangeØ125 to Ø400 mm (9 sizes)
Control ModePressure-Independent
Reheat Duty1-Row / 2-Row (1.6–34.6 kW)
Select a VAV Terminal Performance Sizing Table
YFVAV-S-T100 single-duct variable air volume terminal box
Pressure-Independent Zone Control 122–6,232 m³/h · Multi-Point Cross Sensor · Optional Hot-Water Reheat
01 / Flow Control Physics

Zone-Control Problems Appear When Airflow Is Controlled by Damper Position Alone

A room can be comfortable during balancing and drift out of control once neighboring zones open or close, altering main duct static pressure.

A pressure-dependent terminal moves its damper based on thermostat demand alone; if upstream duct pressure shifts, actual delivered airflow changes even though the damper position hasn’t moved.

A pressure-independent terminal measures actual airflow through an integrated multi-point sensor and dynamically readjusts damper position to maintain the commanded volume regardless of static pressure swings in the supply duct.

Oversizing leads to unstable minimum-flow control at the bottom of the sensor range, while undersizing creates excessive inlet pressure drop and acoustic breakout noise.

VAV terminal box installation in commercial building ceiling space

ASHRAE Handbook — Air Handling and Distribution defines pressure-independent VAV operation: the room thermostat resets the required airflow setpoint between scheduled minimum and maximum limits, while the terminal independently maintains measured flow.

Pressure Independence

Integrated flow sensor and actuator loop holds CFM setpoints constant regardless of upstream main duct pressure fluctuations.

Cross-Sensor Measurement

Low Static Pressure Drop

Aerodynamic internal blade and flow sensor profile achieves minimal pressure loss as low as 2 Pa at wide-open design flow.

Low Pressure Loss

Hot-Water Reheat (1–2 Row)

1-row (1.6–17.5 kW) or 2-row (2.7–34.6 kW) hot-water coils provide sensible perimeter heating during minimum ventilation flow.

1.6–34.6 kW Heating Duty
02 / Performance Sizing Matrix

Match the Inlet Size to the Real Operating Airflow Range

The YFVAV-S-T100 family contains nine documented sizes spanning 122 to 6,232 m³/h.
Model Code Minimum Airflow Maximum Airflow Inlet Diameter Box Dimensions (Z × X × Y)
YFVAV-S-T100-05
 122 m³/h 612 m³/h
Ø125 mm
 400 × 270 × 280 mm
YFVAV-S-T100-06
 176 m³/h 880 m³/h
Ø150 mm
 400 × 270 × 280 mm
YFVAV-S-T100-07
 238 m³/h 1,190 m³/h
Ø175 mm
 400 × 320 × 280 mm
YFVAV-S-T100-08
 312 m³/h 1,560 m³/h
Ø200 mm
 400 × 320 × 280 mm
YFVAV-S-T100-09
 394 m³/h 1,972 m³/h
Ø225 mm
 400 × 370 × 330 mm
YFVAV-S-T100-10
 486 m³/h 2,430 m³/h
Ø250 mm
 400 × 370 × 330 mm
YFVAV-S-T100-12
 700 m³/h 3,500 m³/h
Ø300 mm
 450 × 420 × 380 mm
YFVAV-S-T100-14
 952 m³/h 4,760 m³/h
Ø350 mm
 500 × 470 × 430 mm
YFVAV-S-T100-16
 1,246 m³/h 6,232 m³/h
Ø400 mm
 500 × 520 × 480 mm
Note: Control enclosure dimensions standard at 300 × 120 × 250 mm. Integrated terminal length Z = 1,000–1,100 mm. For high-capacity requirements exceeding 6,232 m³/h, refer to the YF-VTT high-capacity series.
03 / Application Configurations

Select the Configuration That Fits the Zone and Ceiling Space

Cooling-only, acoustic attenuator lined sections, hot-water reheat coils, and YF-MOA multi-outlet distribution plenums.
Configuration 01 · Standard Office Zones Cooling-Only · Models -08 to -10

Standard Single-Duct VAV for Commercial Offices

Base YFVAV-S-T100 configuration for interior zones requiring pressure-independent primary cooling modulation. Controls airflow directly in response to zone temperature sensors.

Interior ZonesOffice open-plan floors without perimeter heat loss
BMS IntegrationModbus / BACnet MS/TP DDC direct digital control
Compact DepthEasily fits tight ceiling voids with low profile height
Fast BalancingAutomated electronic sensor calibration during commissioning
Configure Standard VAV
Standard single duct VAV terminal in office building
Standard VAV Series Interior Zone Cooling · Pressure-Independent · DDC BACnet Integration
Configuration 02 · Sound-Sensitive Spaces 914 mm Lined Silencer Section

Acoustic Attenuator Configuration for Hotel Guest Rooms & Meeting Spaces

Incorporates an integrated 914 mm lined acoustic silencer section downstream of the damper assembly to eliminate regenerated air noise and duct-borne sound.

Acoustic Attenuator914 mm internal sound-absorbing liner eliminates blade turbulence hiss
Quiet OperationMeets NC 30 / NC 25 criteria for luxury hotel suites and boardrooms
Typical SizingModels -07 and -08 with factory-matched silencer section
Submittal DataDischarge sound power and radiated sound power curves available
Configure Acoustic VAV
Acoustic silencer section on VAV terminal box
Acoustic VAV Series 914 mm Lined Attenuator · Low NC Target · Hotel & Conference Rooms
Configuration 03 · Perimeter & Healthcare Zones 1-Row / 2-Row Coil · 1.6–34.6 kW

Hot-Water Reheat for Perimeter Zones & Hospitals

Equipped with a factory-installed 1-row or 2-row copper-tube aluminum-fin hot-water coil. Modulates primary cool air for ventilation while heating water coil satisfies perimeter envelope transmission losses.

1-Row Capacity1.6–17.5 kW heating output (entering water 49–88 °C)
2-Row Capacity2.7–34.6 kW extended capacity for cold-climate perimeters
Valve OptionsFactory 2-way or 3-way modulating control valve package
Healthcare UseModels -09 / -10 typical for hospital patient rooms and clinics
Configure Reheat VAV
VAV terminal with hot water reheat coil installed
Reheat VAV Series 1-Row / 2-Row Hot Water Coils · 1.6–34.6 kW · Perimeter Thermal Comfort
Configuration 04 · Downstream Air Distribution YF-MOA Plenums · Types A to F

YF-MOA Multi-Outlet Distribution Plenums

Attaches to the terminal discharge to divide air directly among multiple ceiling swirl, slot or square diffusers via flexible ducting, eliminating complex branch sheet metal ductwork.

Standard LayoutsSix standard outlet arrangements (Types A–F) with circular spigots
Internal LiningAcoustically lined plenum casing reduces airflow discharge turbulence
Installation SpeedPlugs directly into flexible duct runs to speed ceiling fit-out
Assembly OptionsSupplied separately or factory-integrated with YFVAV-S-T100
View YF-MOA Plenums Request Plenum Sizing
YF-MOA multi-outlet distribution plenum box
YF-MOA Plenums Types A–F Outlet Configurations · Integrated Lining · Multi-Diffuser Feed
04 / Procurement Protocol

What Information Is Needed for VAV Terminal Sizing?

Essential inputs to confirm before ordering YFVAV-S-T100 terminals.
VAV Sizing Checklist

Key Sizing Parameters

Submitting your minimum and maximum airflow schedule, available inlet static pressure, acoustic target, reheat parameters, and BMS protocol enables our engineers to provide complete submittal schedules.

1. Scheduled Minimum & Maximum Airflow (m³/h / CFM)
2. Available Inlet Static Pressure & Part-Load Range (Pa)
3. Round Inlet Diameter (Ø125 to Ø400 mm)
4. Hot-Water Reheat (Entering Water/Air Temp, Required kW)
5. Acoustic Requirement (NC / RC Target, Attenuator Need)
6. Control Integration: Modbus / BACnet MS/TP DDC
7. Multi-Outlet Plenum Requirement (YF-MOA Type A–F)
8. Ceiling Void Clearance & Service Panel Access
05 / Manufacturing Standards

10,000 m² Dedicated Plant and Factory Batch Testing

Manufactured in a 10,000 m² production facility with CNC automated bending, certified coil fabrication, and complete factory batch testing.
Precision Fabrication

10,000 m² CNC Production

Fabricated using precision CNC punch presses, automated folding lines, and dedicated coil tube-expanding, fin-pressing, and brazing machinery.

Batch QA Testing

Pressure & Airflow Inspection

Reheat coils receive 100% pneumatic pressure leak testing; completed VAV boxes are tested for airflow sensor calibration and mechanical operation before crating.

Traceability

Unique Serial Code Tracking

Each terminal is tagged with a unique serial identifier linking factory calibration curves, actuator configurations, and inspection records.

Lead Time & Supply: Standard order production lead time typically 7–15 working days with export seaworthy packaging. Trade terms supported: EXW, FOB, CIF, DDP.
06 / Architectural Boundaries

A VAV Terminal Cannot Fix Incorrect Zone Design

Understanding the proper system limits of single-duct VAV terminals.

Thermal Zoning Integrity

Do not use one terminal to serve spaces requiring independent temperature setpoints just because a multi-outlet plenum can feed multiple rooms.

Zoning Rule

Inlet Sizing & Velocity

Do not simply select the smallest inlet that can hit maximum airflow if the resulting velocity creates excessive acoustic noise or pressure drop.

Acoustic Balance

High-Capacity Above 6,232 m³/h

For airflow demands exceeding the 6,232 m³/h round-duct limit, transition to the high-capacity YF-VTT series rather than extrapolating S-T100.

YF-VTT Routing
ALERTS — NOT PART OF THE PAGE. RESOLVE BEFORE PUBLISHING.
Ensure AHRI 880 acoustic and aerodynamic ratings match certified submittal data for international projects requiring certified sound power levels.
Confirm DDC controller protocol (BACnet MS/TP vs BACnet/IP) and factory mounting vs field mounting with the control contractor before final shipment.
The source references high-capacity series YF-VTT for flows above 6,232 m³/h; obtain the complete YF-VTT catalog data prior to publishing dedicated high-volume pages.
07 / Technical Q&A

Single-Duct VAV Terminals Frequently Asked Questions

Direct engineering answers covering pressure independence, airflow ranges, inlet sizing, hot-water reheat coils, and acoustic silencers.

What does pressure-independent mean on the YFVAV-S-T100?

The YFVAV-S-T100 measures airflow and adjusts its damper so the commanded zone airflow is maintained as upstream duct pressure changes within the usable operating range.

What airflow range does the YFVAV-S-T100 cover?

Across all nine documented sizes, the family covers 122–6,232 m³/h (approx. 72–3,668 CFM).

What inlet sizes are available?

The documented round inlets run from Ø125 to Ø400 mm across models -05 through -16.

Which model should I use around 1,500 m³/h?

Several YFVAV-S-T100 sizes overlap around that airflow (e.g. -08, -09, -10). Select from minimum and maximum flow, inlet velocity, available static pressure, acoustic requirement and ceiling space.

Can the terminal provide heating?

Yes. YONGFAN offers 1-row or 2-row hot-water reheat coils. Indicative family heating capacities are approximately 1.6–17.5 kW and 2.7–34.6 kW, respectively.

Is an acoustic option available?

Yes. The supplier documents a 914 mm lined attenuator section for noise-sensitive hotel guest rooms and executive spaces.

Can one VAV terminal feed several diffusers?

Yes. Pair the YFVAV-S-T100 with the YF-MOA Multi-Outlet Distribution Plenum where several diffusers belong to the same control zone.

Can it connect to a BMS?

The supplier source supports Modbus / BACnet integration. Confirm the controller and required points list for the ordered configuration.

08 / Application Engineering Handoff

Select a Single-Duct VAV Terminal

Connect minimum and maximum airflow, inlet diameter, pressure drop, acoustics, reheat duty, and BMS protocol into one confirmed terminal schedule. Send your zone schedule to our application engineers.

122–6,232 m³/h Ø125 to Ø400 mm Inlets Pressure-Independent DDC Modbus / BACnet MS/TP 1-Row / 2-Row Reheat (1.6–34.6 kW) 914 mm Lined Attenuator YF-MOA Plenums (Types A–F)
Select a VAV Terminal Go to Selection Center Ask an HVAC Engineer
YONGFAN application engineers reviewing VAV terminal schedules
Direct Technical Selection Support
Airflow sizing calculations, reheat capacity selections, and certified CAD submittals.
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