Choosing the wrong controller, actuator, balancing device or valve can cause unstable room control, incorrect branch flow, leakage, excessive pump head or failed commissioning.
Explore YONGFAN thermostats (DA / DB / K206), sensors and floating controllers (TC-8000), thermal and motorized linear actuators (VA Series), FCU and AHU control valves (EDV / KYQ), dynamic balancing valves (BYF / KYEJ), 100X–900X pilot hydraulic valves, and general HVAC line valves.
Installing a valve-only thermostat (DA) where the occupant expects 3-speed fan switching (DB) leaves fan speeds unmanaged at setpoint.
Wiring 230 V line-voltage thermostats directly to 24 V valve actuators destroys actuator coils without interposing transformers.
Operating dynamic balancing valves below 20 kPa leaves internal regulators unengaged, allowing uncontrolled overflow into index branches.
Omitting upstream strainers before 100X–900X pilot circuits allows pipe scale to plug small orifices, causing main valve hunting or sticking.
DA (K-01) controls the motorized valve while the fan runs independently. DB (K Series) controls the valve and 3-speed fan synchronously (AC 180–260 V, <1 W, ±1 °C). K206 provides mechanical dial control with built-in master switch and 220 V to 24 V step-down output.
TC-8000 electronic/LCD floating-point controllers (0–40 °C / 0–99 °C) paired with NTC 10k sensors (0–150 °C, IP54). P74JA3 differential-pressure threshold switches (0.5–4 MPa), HFS paddle flow switches (15 bar, SPDT), and packaged temperature/DP control cabinets.
Thermal actuators with PTC wax element (M30×1.5, 110 N thrust, 2 VA, 3–5 min stroke, NC/NO, 230/24/110 V). VA motorized linear actuators (VA3100/VA3200/VA7200 on/off 30 mm; VA7400 modulating 30/38 mm with 0–10 V, 4–20 mA, feedback & manual override).
FCU 2-way replacement valves (DN15–DN25, Johnson/Siemens/Honeywell footprints), 3-wire on/off ball valves, 2-wire fail-in-place ball valves, EDV dynamic balancing 2-way valves (DN20/DN25, 4 bar close-off), KYQ modulating ball valves (DN32–DN100, AC 24 V, spring return), and VG3000 proportional globe valves.
DRV & KPF static manual balancing valves (DN15–DN600, lockable setting, ±5% accuracy). BYF & B-Type dynamic automatic balancing valves (DN15–DN800, 20–300 kPa ΔP). ZYC self-actuated differential-pressure controllers, and KYEJ electric static balancing valves (0–10 V / 4–20 mA, flow verification).
Pilot-operated main valve platform (diaphragm ≤DN450 / piston ≥DN500, PN1.0/1.6/2.5 MPa, 0–80 °C). 100X Remote Float, 200X Pressure Reducing, 300X Slow-Closing Check, 400X Flow Control, 500X Relief/Sustaining, 600X Electric Control, 700X Pump Control, 800X DP Bypass, and 900X Emergency Shut-Off.
Brass threaded valves (ISO 228, PN16, -20–120 °C: ball, gate, stop, check, Y-strainer, air vent, Y13X PRV). 304/316 stainless threaded valves. Butterfly valves (D71X wafer, D371X lug, D341X flanged, SD341X telescopic, D373H metal hard-sealed up to 550 °C, DN50–DN2000). Resilient-seated gate valves (Z45X/Z41X).
| Product Family | What It Solves | Published Range Boundary | First Input to Confirm | Action |
|---|---|---|---|---|
| Thermostats | Room-level FCU temperature and fan/valve sequencing | DA valve-only; DB valve + 3-speed fan; AC 180–260 V, 5–35 °C | Required sequence at setpoint & fan speed wiring | View Thermostats |
| Sensors & Controllers | Measured temperature, pressure status and controller output | TC-8000 (0–40/99 °C), NTC 10k (0–150 °C), P74JA3 (0.5–4 MPa), HFS | Controlled variable and required output signal | View Controllers |
| Actuators | Converts electrical command into valve mechanical stroke | Thermal M30×1.5, 110 N, 2 VA, NC/NO; VA 30/38 mm linear | Valve stem interface and unpowered fail position | View Actuators |
| Motorized Control Valves | On-off or proportional water-flow control across coils | FCU 2-way DN15–DN25; EDV PICV DN20/DN25; KYQ DN32–DN100 | Flow-control mode (On/off vs Mod), DN & ΔP | View Control Valves |
| Balancing Valves | Maintains or adjusts branch/terminal design hydronic flow | DRV/KPF static; BYF dynamic DN15–DN250; 20–300 kPa, PN1.6 MPa | Design branch flow & available differential pressure | View Balancing |
| Hydraulic Control Valves | Pressure, level, pump, flow and DP functions on large mains | 100X–900X, diaphragm ≤DN450 / piston ≥DN500, PN1.0/1.6/2.5 MPa | Hydraulic function, pipe DN & pressure grade | View Hydraulics |
| General HVAC Valves | Isolation, check, straining, venting and manual pressure reduction | Brass ISO 228, PN16; Stainless 304/316; Butterfly DN50–DN2000 | Pipe function, body material & connection type | View General Valves |
FCU fan sequence at setpoint (independent vs stop), modulating vs on/off loop action.
Design flow rate (m³/h, L/s), fluid temperature, and available branch differential pressure.
Supply voltage (230 V / 24 V), control signal (3-wire, 0–10 V, 4–20 mA, floating).
Specify unpowered fail state: Normally Closed (NC), Normally Open (NO), or Fail-in-Place.
YONGFAN application engineers will verify valve authority, match actuator torque and stroke, check thermostat wiring, and provide unified control submittals.
DA/DB thermostat and TC-8000 controller PCBs undergo automated optical inspection and powered heat-chamber aging.
Every assembled motorized valve body and hydraulic valve undergoes 1.5× rated pressure hydrostatic shell and seat leak testing.
Motorized valves and actuators are matched and 50-cycle dry run-tested to verify limit switches, torque, and stem alignment.
Products are manufactured to IEC 60730 electrical safety and EN 12266-1 / API 598 pressure testing frameworks.
Use the DA (K-01) family when the thermostat should control the water valve while fan operation remains independent. Choose DB (K Series) if the fan must switch with the valve.
Start with Motorized Control Valves. YONGFAN documents FCU 2-way valves in DN15–DN25, and EDV for pressure-independent flow control.
The YONGFAN Thermal Actuator uses an M30 × 1.5 connection (110 N thrust, 2 VA, NC/NO). Confirm stem travel and unpowered state before ordering.
For terminal or branch balancing, review Balancing Valves (BYF / KYEJ). For system-level DP bypass on main headers, review 800X Hydraulic Valves.
The KYQ modulating motorized ball valve covers DN32–DN100 with AC 24 V control, spring-return fail-close, and proportional modulation.
Review the 200X Pressure Reducing Valve in the hydraulic control family. For small threaded lines, review the brass Y13X-16T pressure reducer.
Use General HVAC Valves (ball, gate, and butterfly). Do not specify motorized control valves solely for manual maintenance shutoff.
Combine a DA or DB thermostat with a matching motorized 2-way valve (or EDV PICV) and manual or dynamic balancing valves.
Valves regulate system flow; they cannot create pump head or compensate indefinitely for undersized distribution piping.
DA/DB thermostats handle local terminal sequencing. Complex multi-variable AHU routines require dedicated DDC controllers.
This category covers water-side valves. Fire, smoke, and volume-control dampers belong in the dedicated air distribution portfolio.
Never size modulating control valves by line DN alone; verify design flow rate and valve authority to prevent hunting.
Send your control narrative, FCU/AHU schedules, design water flow rates, and operating pressures. YONGFAN application engineers will calculate valve sizing, match actuators and thermostats, and provide unified submittal schedules.
