The Caleffi 656404 is a 24V thermo-electric actuator, normally closed, drawing 125 mA holding current. It mounts on a Caleffi radiator valve, zone valve or distribution manifold and opens or closes it on a room thermostat or switch signal.
Best for multi-zone radiator and manifold control where a high actuator count would otherwise force an oversized transformer, and where a motorised actuator would be audible.
Specifications from Caleffi datasheet 01198/23 NA (replaces 01198/14 NA). Reviewed August 2026.
Key Features
Low In-Rush Current
Starting current is 250 mA or less and holding current is 125 mA, so a high number of actuators can be wired to common controllers and thermostats without oversizing the transformer.
Silent Operation
A PTC resistor heats a wax element to drive the stroke. There is no motor or gear train, so the actuator is silent in occupied spaces.
NEMA 3 in Any Orientation
Seals, o-rings and a cable grommet give NEMA 3 (IP 54) protection in all mounting positions, including upside-down below a ceiling radiant panel or an inverted underfloor manifold.
Open / Closed Position Indicator
A central disc rises and a green circular indicator appears when the valve is open, so operation can be verified at commissioning without energising the whole system.
Quick-Coupling Mount
An M30 x 1.5 manual coupler and retaining clip allow the actuator to be fitted, rotated for cable routing and removed by hand.
Technical Specifications
| Product Type | Thermo-Electric Actuator |
| Series | 6564 Series |
| Operation | Normally closed |
| Electric supply | 24 V (ac) or 24 V (dc) |
| Starting (in-rush) current | 250 mA or less |
| Holding current | 125 mA |
| Running power consumption | 3 W |
| Protection class, all positions | NEMA 3 (IP 54) |
| Insulation | Double insulation construction, CE |
| Opening time, 80% | 300 s |
| Opening time, 100% | 600 s |
| Closing time | 240 s |
| Available stroke length | 4 mm |
| Length of supply cable | 31.5 in (80 cm) |
| Valve connection | M30 x 1.5 |
| Protective shell | Self-extinguishing polycarbonate, white ral 9010 |
| Medium working temperature range | 40 to 170°F (5 to 75°C) |
| Ambient temperature, operation | 32 to 120°F (0 to 50°C), 85% max. humidity |
| Ambient temperature, storage | 20 to 120°F (-5 to 50°C), 95% max. humidity |
| Height | 2-3/4 in |
| Diameter | 2-3/8 in |
| Weight | 0.4 lb |
Documentation
Related Products
- Caleffi 656414 : Thermoelectric Actuator 24V with Auxiliary Microswitch
- Caleffi 220400A : Angled TRV Body 1/2" NPT
- Caleffi 221400A : Straight TRV Body 1/2" NPT
- Caleffi 338452 : Convertible Angled TRV Body
Frequently Asked Questions
What does the Caleffi 656404 do?
It is a 24V thermo-electric actuator. On a thermostat or switch signal a PTC-heated wax element expands and opens the valve it is mounted on; when power is removed the valve returns closed. It replaces a motorised actuator and operates silently.
What is the difference between the 656404 and the 656414?
They are electrically and mechanically identical apart from the end-switch. The 656404 has no auxiliary micro-switch and has a white RAL 9010 shell; the 656414 adds the micro-switch and has a grey RAL 9002 shell.
Can the Caleffi 656404 be mounted upside down?
Yes. NEMA 3 (IP 54) protection applies in all installed positions, which allows inverted mounting on ceiling radiant panel systems or on a manifold installed below the heated space. Tighten the locking nut fully.
How long does the Caleffi 656404 take to open?
It reaches 80 percent open in 300 seconds and full open in 600 seconds. Closing time is 240 seconds. Available stroke is 4 mm.
Which valves does the Caleffi 656404 fit?
It uses the standard Caleffi M30 x 1.5 quick-coupling and fits compatible Caleffi zone valves, distribution manifolds and radiator valve bodies including the 220, 221, 338, 339, 663, 668 S1 and 676 series.
- Product Type:
- Thermoelectric Actuator
- Product Family:
- Actuators
- Series:
- 6564 Series
- Supply Voltage:
- 24 VAC or 24 VDC
- Operation:
- Normally Closed
- Auxiliary Switch:
- No
- Enclosure Rating:
- NEMA 3 (IP 54)
- Valve Connection:
- M30 x 1.5
