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Valve & Hydronic Selection Guide | YONGFAN
Hydronic Control, Balancing & Plant Equipment

Valve & Hydronic Selection: System Functions & Control Sequences

Hydronic selection starts with the system function: pressure maintenance, water supply, flow control, balancing, isolation or pump protection. A valve or skid should be chosen only after that function is defined.

Compare YONGFAN FCU motorized 2-way valves (DN15–DN25), EDV pressure-independent valves, KYQ modulating ball valves (DN32–DN100), BYF/KYEJ balancing valves, 100X–900X pilot hydraulic control valves, JFDY/JFWP closed-loop expansion units, and JFHB/JFWZ booster water supply equipment.

FCU Valves DN15–DN25 · DA/DB Thermostats
Modulating & PICV KYQ (DN32–100) · EDV (DN20/25)
Hydraulic Series 100X to 900X Pilot Valves
Plant Room Skids JFDY · JFWP · JFHB · JFWZ
Request Hydronic Selection Review Sizing Guide
Hydronic plant room with balancing valves, control valves and booster pumps
Hydronic System Engineering Function-Driven Selection, Dynamic Authority, Pilot Hydraulics & Closed-Loop Expansion
01 / Engineering Methodology

Do Not Select Valves from Pipe Size Alone

A DN50 pipe can contain very different duties: modulating coil control, branch balancing, pressure reduction, closed-loop expansion, or booster supply. Nominal diameter does not dictate required valve function.
Hydronic piping manifold with balancing valves and motorized actuators
Hydraulic Standards

GB/T 12244–12246 & PN Classes

Per hydronic standards, control and balancing valves must be selected from design flow (m³/h), differential pressure (ΔP), authority (a), actuator signal, and failure state — not pipe nominal bore.

Oversized Control Valves

Matching a motorized control valve to pipe size rather than flow/Kv leads to oversized valves that operate almost entirely in the bottom 10% stroke, causing hunting.

Impact: Severe room temperature oscillation

Balancing vs. Hydraulic Control Confusion

Confusing a branch balancing valve (BYF/KYEJ) with a main pilot-operated pressure reducing valve (200X) or bypass valve (800X) leads to severe hydraulic misapplication.

Impact: Circuit starvation & line over-pressurization

Expansion Equipment as Water Boosters

Attempting to use a closed-loop make-up expansion unit (JFDY/JFWP) for domestic water boosting ignores open-circuit peak flow and booster dynamics.

Impact: Inability to maintain domestic delivery pressure

Actuator Mismatch & Inverted Mounting

Using thermal actuators where fast modulating response is required, or installing motorized ball valve actuators upside down against manufacturer instructions.

Impact: Water ingress & premature actuator burnout

The Hydronic Sizing Sequence

Follow an engineering workflow that isolates the hydraulic duty before choosing hardware:

01 System Function (Control, Balancing, Pilot, Expansion)
02 Design Flow (m³/h) & Available ΔP (kPa)
03 Control Sequence (On/Off vs Modulating vs PICV)
04 Actuator Voltage, Fail State & Connection Type
02 / Valve & Hydronic Equipment

Choosing the Right Valve & Hydronic Architecture

Compare YONGFAN terminal control valves, modulating ball valves, balancing valves, 100X–900X pilot valves, and plant-room expansion/booster equipment.
Category 01 · FCU / EDV / KYQ Terminal & Coil Control · DN15 to DN100

Motorized FCU Valves, PICV & Modulating Ball Valves

Regulating water flow through fan coil units, AHU coils, and zone terminals according to thermostat commands and BMS signals.

FCU Motorized 2-Way Valves (DN15, DN20, DN25): On/off motorized valves coordinated with DA thermostats (independent fan) or DB thermostats (coordinated 3-speed fan, AC 180–260V).
EDV Pressure-Independent Valves (DN20, DN25): Maintains stable flow under varying system differential pressure in variable-flow circuits.
KYQ Modulating Motorized Ball Valves (DN32–DN100): Proportional 0–10V / 4–20mA control, AC 24V supply, spring-return fail-close operation.

FCU Motorized
DN15 · DN20 · DN25 on/off 2-way replacement valves
EDV PICV
DN20 / DN25 pressure-independent flow control
KYQ Modulating
DN32 – DN100 · AC 24V proportional coil control
Thermal Actuators
M30 × 1.5 connection · 110 N force · 2 VA · 3–5 min
Actuator Installation Rule: Never install motorized valve actuators upside down below the horizontal centerline to prevent condensation damage.
View Control Valves Request Valve Sizing
Motorized 2-way fan coil control valve with electric actuator
KYQ Modulating Motorized Ball Valve
Control Valve Logic:
  • FCU on/off for standard fan coil loops
  • EDV PICV for variable flow branch stability
  • KYQ for modulating AHU cooling/heating coils
  • VA linear actuators for 2-way/3-way plug valves
Category 02 · BYF / KYEJ / 100X–900X Hydronic Balancing & Pilot Main-Line Control

Branch Balancing & 100X–900X Hydraulic Control Valves

Establishing intended flow distribution across branches and providing automated pilot-operated regulation on main distribution headers.

Balancing Valves (BYF / KYEJ): BYF covers DN15 to DN250, differential pressure range 20 to 300 kPa, PN 1.6 MPa. Distributes pump head proportionally across all system branches.
100X–900X Hydraulic Control Valves: Pilot-operated diaphragm (≤DN450) and piston (≥DN500) construction, PN 1.0 / 1.6 / 2.5 MPa.
Series include: 100X (Float), 200X (Pressure Reducing), 300X (Slow Closing Check), 400X (Flow Control), 500X (Pressure Relief/Sustaining), 600X (Electric Control), 700X (Pump Control), 800X (Differential Pressure Bypass), and 900X (Emergency Shut-Off).

BYF Balancing
DN15 – DN250 · 20 – 300 kPa ΔP · PN 1.6 MPa
200X Reducing
Pilot-operated downstream pressure reduction
500X Relief
System pressure relief & upstream sustaining
800X Bypass
Differential pressure bypass balancing across headers
Pilot Function First: Always identify the hydraulic pilot function (100X–900X) before specifying body size and pressure class.
View 100X–900X Valves View Balancing Valves
200X pilot operated hydraulic pressure reducing valve in plant room piping
200X Hydraulic Pressure Reducing Valve
Key Hydraulic Functions:
  • BYF for manual branch commissioning balancing
  • 200X for main line water pressure reduction
  • 500X for surge relief & backpressure maintenance
  • 800X for constant chiller/boiler header ΔP bypass
Category 03 · JFDY / JFWP / JFHB / JFWZ Closed Expansion & VFD Booster Water Supply

Plant Room Expansion Skids, Boosters & Water Distributors

Packaged plant room equipment providing closed-loop thermal expansion, make-up pressure stabilization, domestic water pressure boosting, and circuit distribution.

JFDY & JFWP (Closed Expansion): JFDY pressure tank volume 0.20 to 8.53 m³ (0.6, 1.0, 1.6 MPa) absorbs thermal expansion in heating/chilled loops. JFWP is the packaged pump-and-control expansion skid.
JFHB & JFWZ (Water Supply): JFHB VFD constant-pressure booster (8–5,500 m³/h, 20–250 m head, 0.55–315 kW). JFWZ non-negative-pressure booster utilizes incoming municipal network residual head directly.
Water Distributors & Collectors: Custom carbon or stainless headers up to 2.0 MPa.
JFLN Condensate Recovery: Recovers high-temperature steam condensate.

JFDY Expansion
0.20 – 8.53 m³ vessel · 0.6 / 1.0 / 1.6 MPa closed loops
JFHB VFD Booster
8 – 5,500 m³/h · 20 – 250 m head · 0.55 – 315 kW
JFWZ Non-Negative
Municipal residual pressure direct booster connection
Distributors & JFLN
Custom header manifolds · Steam condensate recovery
System Role Separation: JFDY/JFWP are for closed HVAC expansion; JFHB/JFWZ are for open building water supply. Do not interchange make-up skids with booster pumps.
View Booster Equipment View Expansion Skids
JFHB VFD constant pressure booster water supply equipment skid with pumps
JFHB VFD Constant-Pressure Booster Skid
Plant Room Selection Rules:
  • Size JFDY from total loop water volume & static height
  • Size JFHB from peak domestic demand & discharge head
  • Use JFWZ when municipal supply code permits direct boost
  • Coordinate branch nozzle schedules on Distributors
03 / Selection Matrix

Valve & Hydronic Routing Table

Cross-reference YONGFAN valve and plant-room equipment families by system requirement, published boundary, and initial technical inputs.
System Requirement First YONGFAN Family Published Supplier Boundary First Input to Confirm Action
FCU on/off room temperature control
DA/DB Thermostat + FCU 2-Way Valve
 Valve DN15–DN25 · AC 220V on/off actuator Control sequence and actuator voltage Configure FCU
Pressure-independent terminal control
EDV PICV Series
 DN20 / DN25 · Integrated ΔP regulator Design flow and available differential pressure Configure EDV
Larger proportional AHU coil control
KYQ Modulating Ball Valve
 DN32–DN100 · AC 24V · 0–10V / 4–20mA Flow (m³/h), ΔP, signal, and fail position Configure KYQ
Small manifold / zone actuation
Thermal Actuator
 M30 × 1.5, 110 N, 2 VA, 3–5 min stroke Valve thread interface and normal position (NC/NO) Configure Actuator
Branch hydronic flow balancing
BYF / KYEJ Balancing Valves
 BYF DN15–DN250 · 20–300 kPa · PN 1.6 MPa Design branch flow and pipe diameter Configure BYF
Main-line automated hydraulic control
100X–900X Pilot Valves
 PN 1.0 / 1.6 / 2.5 MPa · Diaphragm ≤DN450, Piston ≥DN500 Required hydraulic pilot function (200X, 500X, 800X, etc.) Configure 100X
Manual isolation, check, straining
General HVAC Valves
 Brass family PN 1.6 MPa, −20 to 120°C · Stainless & Butterfly Pipe function, pressure rating, and body material Configure General
Closed-loop make-up & expansion
JFDY / JFWP Skids
 JFDY 0.20–8.53 m³ · 0.6/1.0/1.6 MPa pressure classes System loop water volume and building static height Configure JFDY
Constant-pressure booster water supply
JFHB VFD Booster System
 8–5,500 m³/h · 20–250 m head · 0.55–315 kW Peak water demand flow and required discharge pressure Configure JFHB
Municipal residual-pressure boosting
JFWZ Non-Negative Booster
 Project configured · Direct municipal connection Incoming municipal residual pressure and peak flow Configure JFWZ
Hydronic circuit distribution header
Water Distributor & Collector
 Custom branches · Carbon/Stainless · to 2.0 MPa Total header flow, branch count, and nozzle schedule Configure Header
Steam condensate hot water recovery
JFLN Condensate Recovery
 Project / model dependent packaged skid Condensate flow rate, temperature, and return pressure Configure JFLN
04 / Procurement Protocol

Information Required for Valve & Hydronic Quotes

Submit design flows, differential pressures, control sequences, and loop volumes to freeze valve authorities and plant equipment sizing.
STEP 01

Application & Function

State hydraulic job: terminal FCU control, proportional coil modulation, branch balancing, pilot reduction, or closed expansion.

STEP 02

Flow & Differential Pressure

Provide design flow (m³/h / l/s), upstream pressure, and normal/maximum differential pressure (ΔP) across the valve.

STEP 03

Actuator & Electrical

Specify supply voltage (AC 24V / AC 220V), control signal (on/off vs 0–10V / 4–20mA), and fail position (spring-return NC/NO).

STEP 04

Loop Volume & Pressure

For JFDY/JFWP expansion, provide total loop volume (m³) and static height; for JFHB/JFWZ boosters, provide peak demand and head.

Engineering Handoff

15-Point Hydronic Checklist

Submit your valve schedules or plant room P&ID schematics. YONGFAN hydronic engineers will verify Kv authority, cavitation limits, and expansion tank volumes.

1. Valve Function (Control, Balancing, Pilot, Isolation)
2. Design Flow Rate (m³/h or L/s)
3. Upstream Pressure & Working ΔP (kPa)
4. Pipe Size & Connection (Threaded vs Flanged)
5. Fluid Type (Water, Glycol %, Steam) & Temp (°C)
6. Pressure Class (PN 1.0 / 1.6 / 2.5 MPa)
7. Actuator Voltage (AC 24V / AC 220V)
8. Control Signal (On/Off, 0–10V, 4–20mA)
9. Fail-Safe State (Spring Return NC / NO / Stay)
10. Thermostat Model: DA (Indep) vs DB (Coordinated)
11. 100X–900X Pilot Function (Float, Reduce, Relief)
12. Total System Water Volume (m³) for JFDY/JFWP
13. Building Static Height & Cold Fill Pressure
14. Booster Peak Demand Flow & Discharge Head
15. Existing Valve Dimensions for Replacement Work
05 / Manufacturing Verification

Valve & Skid QA & Hydraulic Testing

Body hydrostatic pressure testing, seat leakage verification, actuator torque/stroke checks, and skid pump performance testing.
Pressure QA

1.5× Body Hydrostatic Test

Valve bodies undergo 1.5× nominal pressure shell testing per GB/T 13927 to ensure zero porosity, casting defects, or wall leakage.

Seat Leakage

1.1× Seat Shut-Off Verification

Valves are seat-tested at 1.1× design pressure to verify bubble-tight shut-off (Class A/B) and prevent internal bypass when closed.

Actuator Testing

Actuator Torque & Stroke QA

Motorized actuators are cycle-tested for rated torque, stroke travel limits, auxiliary switch feedback, and spring-return fail action.

Skid Testing

Plant Room Skid Pre-Commission

JFDY, JFWP, and JFHB skids are pre-wired and hydrostatically tested, verifying VFD pump rotation, pressure sensors, and PLC logic.

06 / Engineering Knowledge

Valve & Hydronics Frequently Asked Questions

Technical answers to key selection questions regarding FCU valves, thermostats, PICVs, 100X–900X pilot series, and booster systems.

Which valve should I use for a fan coil unit?

Start with the FCU Motorized 2-Way Valve in DN15, DN20, or DN25. Match it to the thermostat sequence (DA vs DB), design flow, differential pressure, and AC 220V actuator.

Should I specify a DA or DB thermostat?

Use DA when the thermostat controls the motorized valve while fan operation remains manual/independent. Use DB when the thermostat coordinates both the valve and 3-speed fan.

When should I use EDV instead of a conventional 2-way valve?

Use EDV Pressure-Independent Valves in variable-flow circuits where branch differential pressure fluctuates significantly as other zone valves open and close.

What is the difference between a control valve and a balancing valve?

A control valve dynamically varies flow in response to a thermostat or BMS signal. A balancing valve statically limits branch flow to maintain design hydraulic distribution.

Is 800X the same as a branch balancing valve?

No. 800X is a pilot-operated differential pressure bypass valve for main chiller/boiler headers. BYF / KYEJ are branch-level manual balancing valves.

Which hydraulic control valve reduces pressure?

Use the 200X Pressure Reducing Valve when main-line downstream pressure must be reduced and stabilized below higher upstream supply pressure.

Which product handles closed-loop expansion?

Review JFDY Constant-Pressure Make-Up Units or JFWP Expansion Skids. These are closed-loop pressure maintenance products, not domestic booster sets.

JFHB or JFWZ for building water supply?

Use JFHB for standard VFD booster systems drawing from suction tanks. Use JFWZ where municipal supply codes permit direct booster connection to utilize incoming residual head.

07 / Application Boundaries

Valve & Hydronic Scope Ends at the Mechanical Connection

Understanding system boundaries ensures clear delineation of engineering responsibilities across hydronic plant room installations.
Boundary 01 / Hydraulic Calculation

System Head Loss Sizing

YONGFAN sizes valves to supplied flow and ΔP; calculation of total system head loss, pump curves, and pipe sizing belongs to the MEP consultant.

Boundary 02 / BMS Programming

DDC Control Programming

YONGFAN provides standardized 0–10V/4–20mA actuators and Modbus skids; building management system (BMS) DDC programming belongs to controls contractors.

Boundary 03 / Pipe Cleanliness

Pipeline Flushing & Strainers

Pipelines must be flushed before valve installation; damage caused by welding slag, debris, or missing Y-strainers is excluded from valve warranty.

Boundary 04 / Municipal Permitting

Non-Negative Water Approval

JFWZ skids feature backflow prevention; local water authority connection permitting for direct municipal boosting remains owner scope.

08 / Engineering Handoff

Request Valve & Hydronic Selection

Send your design flow rates, differential pressures, control sequences, and plant room drawings — YONGFAN application engineers will configure optimized control valves, balancing schedules, and packaged expansion skids.

FCU Motorized (DN15–DN25) EDV PICV · KYQ Modulating BYF / KYEJ Balancing Valves 100X–900X Hydraulic Pilot Valves JFDY / JFWP Expansion Units JFHB / JFWZ Booster Skids
Request Hydronic Selection Go to Selection Center Contact Technical Support
Engineers reviewing hydronic valve drawings and pump skid schedules
Hydronic Application Engineering
Kv authority calculation, pilot hydraulic sizing & closed-loop expansion design.
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