Thermal Actuator 920074PL
The 920074PL Thermal Actuator is a Normally Closed electrothermal valve actuator with a built-in auxiliary micro switch that allows it to control a circulation water pump. Manufactured by Legom with a durable glass-fiber reinforced PA66+30%GF housing, it converts a 220V AC supply into smooth, silent valve actuation, delivering a force of 110N and a stroke of ≥3.4mm while drawing only 2W of power.
The integrated micro switch, rated for a maximum of 700mA (up to 3A), changes state as the actuator opens, providing a signal that can start the circulation pump or indicate a heat demand. This makes the 920074PL ideal for underfloor heating manifolds where the pump should run only when at least one zone is open. Supplied with an 800mm four-wire cable, an M30x1.5mm adapter, and an IP54 rating, and built to the EN 60730 standard, it combines dependable thermal actuation with practical pump and demand control in a single unit.
Key Benefits
- Built-in auxiliary micro switch – An integrated switch changes state as the valve opens, providing a signal to start a circulation pump or flag a heat demand without a separate control module
- Water pump control function – Ensures the pump runs only when a zone is actually open, preventing wasted energy and pump dead-heading when all zones are closed
- Normally Closed fail-safe action – The valve closes automatically when power is lost, stopping flow to the circuit, which is the preferred safe default for underfloor heating
- Higher 110N force – Delivers firm, reliable valve actuation across the operating range
- Micro switch rated to 700mA (up to 3A) – Suitable for switching small pump or relay loads directly, with a relay or contactor recommended for larger pumps
- 800mm four-wire cable – Separate conductors for actuator power and the micro switch contact simplify wiring into pump and demand circuits
- Silent, wear-free actuation – The thermal operating principle uses no motor or solenoid, giving quiet operation and long service life with no mechanical switching wear
- IP54 protection grade – Dust and splash protection makes the unit suitable for the typical manifold cabinet and utility-room environment
- EN 60730 compliant – Meets the international standard for automatic electrical controls for household and similar use
- Standard M30x1.5mm adapter – Fits the majority of underfloor heating manifold valves and common zone valve bodies without custom hardware
- OEM and ODM customization available – Force, cable length, adapter thread, and housing can be adapted to specific product and market requirements
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | 920074PL |
| Function | Control water pump (auxiliary micro switch) |
| Voltage | 220V AC |
| Power Consumption | 2W |
| Working Temperature | -5°C to 60°C |
| Force | 110N |
| Control Direction | Normally Closed (NC) |
| Micro Switch | Max 700mA (up to 3A) |
| Closing and Opening Time | 3 to 5 minutes |
| Adapter | M30x1.5mm |
| Cable Length | 800mm (four-wire) |
| Protection Level | IP54 |
| Standard | EN 60730 |
| Stroke | ≥3.4mm |
| Housing Material | PA66+30%GF |
Specifications are typical values for the standard configuration. Refer to the user manual for the complete four-wire wiring diagram and dimensional drawings.
Application & Use Cases
- Underfloor heating with pump control – The primary application, where the auxiliary micro switch starts the circulation pump only when a zone actuator opens, avoiding pump operation against closed valves
- Heat demand signaling – The switch output can be wired to a boiler or controller to signal that at least one zone is calling for heat
- Multi-zone manifold systems – Coordinates pump and zone operation across manifolds serving several rooms or circuits
- Zone valve control – Drives manifold-mounted zone valves in hydronic systems, switching flow to individual circuits on demand
- Thermostat-driven systems – Wired to room thermostats or controllers, translating the call-for-heat signal into both valve movement and pump activation
Installation Notes
- Mount the actuator on a compatible valve using the M30x1.5mm adapter. Confirm the valve thread before installation
- Connect the unit to a 220V AC supply in accordance with EN 60730 and local electrical regulations
- Wire the four-wire cable correctly: two conductors supply the actuator and two carry the micro switch contact to the pump or demand circuit. Follow the wiring diagram in the user manual
- Do not exceed the micro switch rating of 700mA (up to 3A). For pumps or loads above this rating, switch a relay or contactor with the micro switch rather than driving the pump directly
- Because the actuator is Normally Closed, the valve remains shut until energized. Verify this matches the intended control logic for the zone
- Allow for the 3 to 5 minute opening and closing time. Thermal actuators are slow-acting by design and do not respond instantly like solenoid valves
- Observe the IP54 rating. The actuator is protected against dust and splashing water but must not be submerged or installed in fully exposed outdoor locations
- Install the actuator in the recommended upright orientation and keep it within the -5°C to 60°C working range
- For OEM integration, confirm three key parameters in writing before finalizing the order: force, cable length, and adapter thread
Frequently Asked Questions
How does the 920074PL control a water pump?
The actuator contains an auxiliary micro switch that changes state as the valve opens. When wired into the pump circuit, this switch signals the circulation pump to start once a zone opens, and to stop when the zone closes. This means the pump runs only when there is actual flow demand, which saves energy and protects the pump from running against closed valves.
What is the four-wire cable for?
Two of the four conductors supply power to the actuator, and the other two connect the built-in micro switch to the pump or demand circuit. This lets a single unit handle both valve actuation and pump or boiler signaling. Always follow the wiring diagram in the user manual to connect it correctly.
Can the micro switch drive any pump directly?
The micro switch is rated for a maximum of 700mA (up to 3A). Small pumps or relay coils within this rating can be switched directly. For larger pumps, use the micro switch to operate a relay or contactor that carries the pump load, rather than driving the pump through the switch itself.
What does Normally Closed mean?
A Normally Closed (NC) actuator keeps the valve closed when it is not powered and opens only when energized. If power is lost, flow to the circuit stops automatically. This fail-safe behavior is the preferred default for underfloor heating.
Which valves is the 920074PL compatible with?
The actuator connects through an M30x1.5mm adapter, which fits the majority of underfloor heating manifold valves and common zone valve bodies. Confirm that your valve uses the M30x1.5 thread before ordering.
Can the 920074PL be customized for OEM projects?
Yes. Legom offers full OEM and ODM services. Force, cable length, adapter thread, and housing details can be adapted to your product requirements. Written confirmation of three key parameters is required before a customization project begins: force, cable length, and adapter thread. Contact us via WhatsApp or email to start the process.
OEM & ODM Customization
Legom supports full OEM and ODM services for the 920074PL Thermal Actuator with auxiliary micro switch. Our engineering team can customize the force, cable length, adapter thread, and housing to match your product requirements. Before any commitment, written confirmation of three key parameters is required: force, cable length, and adapter thread. All customization projects are handled with strict confidentiality. Contact us via WhatsApp or info@legomsmart.com.
User Manual
Product information last reviewed by the Legom Technical Team. For the most current specifications, refer to the official user manual or contact our sales team.
Custom OEM & ODM Solutions
Legom is a direct manufacturer offering end-to-end OEM and ODM services. With our in-house engineering and production capabilities, we work closely with distributors and system integrators to deliver fully customized solutions under strict NDA.
