The Caleffi 656404 is a 24V thermoelectric actuator. It opens and closes a radiator or zone valve on a thermostat signal, silently and at low current draw.
Best for zone control where motorized actuators would be audible or would overload the transformer.
Specifications sourced from Caleffi North America technical literature. Last reviewed July 2026.
Key Features
Low Current Draw
A thermoelectric element opens and closes the valve on a 24V signal, drawing far less current than a motorized actuator and allowing more zones per transformer.
Silent Operation
No motor or gear train, so the actuator is silent in occupied spaces.
Technical Specifications
| Product Type | Thermoelectric Actuator |
| Ambient temperature range | 0-50 deg C |
| Protection class | NEMA 3 (IP 54) |
| Supply cable length | 31.5 in (80 cm) |
| Supply voltage | 24 VAC or 24 VDC |
| Operation | Normally closed |
| Starting (in-rush) current | less than or equal to 250 mA |
| Holding current | 125 mA |
| Running power consumption | 3 W |
| Opening time (80%) | 300 s |
| Opening time (100%) | 600 s |
| Closing time | 240 s |
| Available stroke length | 4 mm |
| Series | Accessories |
| Shipping Weight | 0.4 lb |
Documentation
Related Products
- Caleffi 656414 : Thermoelectric Actuator 24V with Auxiliary Microswitch
- Caleffi 200000 : Control Head, Built-in Sensor
- Caleffi 201000 : Control Head, Remote Sensor
- Caleffi 203502 : Control Head, Contact Probe
Frequently Asked Questions
What does Caleffi 656404 do?
It is a 24V thermoelectric actuator. It opens and closes a radiator or zone valve on a thermostat signal using a heated element rather than a motor, so it is silent and draws low current.
What is the warranty on Caleffi 656404?
Caleffi covers this product under its standard two-year limited warranty against defects in material and workmanship from the date of shipment. ZOT Supply is an authorized Caleffi distributor.
- Product Type:
- Thermoelectric Actuator
- Product Family:
- Thermostatic control heads
- Series:
- Accessories
