Merten Thermal Actuator 639125

Heating installers and facility managers use the Merten Thermal Actuator 639125 to control heating circuit distributors and zone valves in residential and commercial buildings. This thermal actuator operates on 230 V AC and is normally closed, opening when powered to allow flow. It features an M30 x 1.5 mm connection thread for direct mounting on valve bodies. The actuator provides a visual position indicator for quick status checks. With an actuating force of 100 N and a stroke of 3.5 mm, it reliably operates compatible valves. The housing is made of white plastic (RAL 9010) and the unit has a 1-meter connection cable. It is suitable for ambient temperatures from 0 to 60 °C.

Key specifications

• Operating voltage: 230 V AC
• Function: Normally closed (NC)
• Connection thread: M30 x 1.5 mm
• Power consumption: 1.8 W
• Actuating force: 100 N
• Stroke: 3.5 mm
• Cable length: 1 m
• Ambient temperature range: 0 to 60 °C
• Housing material: Plastic (PC)
• Colour: White (RAL 9010)
• Closing time: approx. 3 minutes
• Opening time: approx. 5 minutes
• Inrush current: max. 200 mA for 200 ms
• Mounting type: Screw connection

Why choose it

The Merten 639125 offers reliable thermal actuation for heating zone control. Its compact design and standard M30 thread allow easy installation on common valve bodies. The visual position indicator simplifies system checks, and the 1-meter cable provides flexibility in wiring.

Ideal use cases

• Controlling zone valves in underfloor heating manifolds
• Actuating radiator valves in central heating systems
• Automating heating circuits in residential and commercial buildings

Good to know

The actuator is designed for screw mounting and is compatible with heating circuit distributors and zone valves. It operates on 230 V AC and has a low power consumption of 1.8 W.