An actuator can match the controller electrically and still fail the valve mechanically. Thread, stroke, thrust, control signal and unpowered position all have to agree before the loop can work.
Compare YONGFAN Thermal Actuators (M30×1.5, 110 N, wax PTC, NC/NO) and motorized linear actuators (VA3100, VA3200, VA7200 on/off 30 mm stroke, and VA7400 modulating 30/38 mm with 0–10 V, 4–20 mA, position feedback, and manual override).
M30×1.5 thread only confirms mounting nut geometry; it does not verify whether valve stem travel or required seat closing force (110 N) agree.
Assuming motorized actuators have spring return. The documented VA family holds last position upon power cut; spring return requires specific models.
Connecting a 0–10 V or 4–20 mA analog BMS signal to an actuator (VA3100/VA3200) configured only for 3-wire on/off or floating control.
Applying a 3–5 min thermal wax actuator to an AHU discharge air loop requiring 30-second mechanical response creates severe thermal overshoot.
Uses a wax-expansion element heated by a PTC resistor (2 VA power consumption, 110 N thrust, 3–5 min full stroke). Fitted with an M30×1.5 threaded collar, 1000 mm cable, visual position indicator, IP44 protection, and flame-retardant PC/PA66 housing. Available in Normally Closed (NC) or Normally Open (NO).
Entry linear motorized actuator using a low-voltage reversible synchronous motor, internal end-position limit switches, visual position indicator, and flame-retardant ABS housing for central air-conditioning, chilled-water, and hot-water 2-way and 3-way valves.
Motorized linear-stem actuators documented around a 30 mm stroke class. Feature reversible synchronous motor drive, internal travel-limit switches, visual position indicator, and flame-retardant ABS construction for 2-way and 3-way linear control valves.
Feature-complete motorized linear actuator supporting on/off or modulating control with analog inputs (0–10 V, 2–10 V, 0–20 mA, 4–20 mA) and position feedback (0–10 VDC / 2–10 VDC). Supports 30 mm or 38 mm stroke and includes integrated manual override.
| Selection Field | Thermal Actuator | VA3100 / VA3200 / VA7200 | VA7400 |
|---|---|---|---|
| Typical Valve Type | Manifold, small control valve, PICV / EDV body | Linear 2-way / 3-way control valve | Linear 2-way / 3-way modulating control valve |
| Motion Source | Wax expansion + PTC heating element | Reversible synchronous motor | Reversible synchronous motor |
| Control Role | On / Off | On / Off | On / Off or Analog Modulating |
| Mounting Interface | M30 × 1.5 threaded collar | Matched linear valve yoke mount | Matched linear valve yoke mount |
| Stroke Travel | Terminal travel (~3–5 mm) | 30 mm stroke class | 30 mm or 38 mm selectable |
| Thrust Force | 110 N nominal | Confirm by valve model | Confirm by valve model |
| Full-Stroke Response | 3 – 5 minutes | Motor drive (~30–90 s) | Motor drive (~30–90 s) |
| Control Signal | Energize / De-energize (NC/NO) | 3-wire on / off or floating | 0–10 V, 2–10 V, 0–20 mA, 4–20 mA |
| Position Feedback | Visual indicator | Visual pointer | 0–10 VDC / 2–10 VDC feedback |
| Manual Override | None | None | Integrated Manual Override |
| Unpowered Behavior | NC or NO selected at order | Holds last position | Holds last position |
M30×1.5 thread (Thermal) or specific linear yoke mounting collar and stem travel (mm).
Required closing thrust (110 N vs large linear force) and stroke length (30 mm vs 38 mm).
On/Off (NC/NO), 3-wire floating, or modulating analog (0–10 V / 4–20 mA) with feedback.
Specify supply voltage (230 V / 24 V), manual override need, and enclosure rating.
YONGFAN application engineers will verify stem stroke alignment, confirm BMS analog signal compatibility, and check actuator thrust against valve close-off ΔP.
Thermal actuators are tested on load fixtures to verify 110 N force and 3–5 min full-stroke timing at 25 °C ambient.
VA-series synchronous motor gear trains are tested against calibrated mechanical load fixtures across full travel.
VA7400 actuators undergo full analog signal sweeps (0–10 V / 4–20 mA) and cross-checking of position feedback voltages.
High-voltage dielectric withstand tests and internal travel limit switch cutoffs are 100% verified on all production lots.
Start with the YONGFAN Thermal Actuator. It uses an M30 × 1.5 threaded collar (110 N thrust, 2 VA, NC/NO). Confirm valve stem travel before approving.
NC (Normally Closed) leaves the valve closed when unpowered and opens when energized. NO (Normally Open) provides the opposite unpowered logic.
Not for radiant floor slabs or manifold zones, where building thermal mass responds over hours. For fast AHU air loops, specify motorized VA actuators.
The VA7400 family supports 0–10 V and 2–10 V inputs, as well as 0–20 mA and 4–20 mA current loops, plus position feedback.
VA7400 provides 0–10 VDC or 2–10 VDC analog position feedback. Feedback is not standard on VA3100, VA3200, or VA7200 on/off models.
VA7400 supports 30 mm or 38 mm stroke compatibility depending on the matched linear valve body.
The documented VA synchronous motor architecture holds its last position rather than automatically springing to an end position.
No. Current documentation classifies VA3100 as on/off. Use VA7400 when analog modulating control is required.
This category covers hydronic valve actuators. Fire/smoke dampers, VAV rotary actuators, and air dampers belong under air distribution.
Thermal actuators require 3–5 min to stroke. Do not specify thermal actuators where rapid emergency emergency shut-off is required.
Standard VA motorized actuators hold position on power loss. Fail-safe spring return must be explicitly specified.
An M30×1.5 thread does not prove stem travel matches. Always verify valve body closing force and travel depth.
Send your valve body model, mounting thread/yoke, required stroke, available control voltage, and signal format. YONGFAN application engineers will verify mechanical fit, electrical compatibility, and provide complete submittal documentation.
