Thermostatic valves
Thermostatic valves are a self-regulating solution for heating and cooling systems, providing reliable control without electricity. Each such self-acting component is most often used where precise limiting of the return temperature in district heating (DH) networks, or efficient DHW preparation in storage heaters, is required.
Danfoss AVTB series and technical characteristics
The Danfoss AVTB is a direct-acting valve whose complete solution consists of two parts: the valve body and the thermostatic sensor. Standard models cover DN15, DN20 and DN25 diameters with different flow capacity (Kv) values and are designed for the PN16 pressure class. It is important to pay attention to these parameters:
- Operating principle: The valve closes as the temperature rises, so it is intended for heating modes.
- Temperature ranges: Depend on the selected sensor code. Available options: 0-30°C, 20-60°C or 30-100°C.
- Capillary length: The standard length is 2 m (2.3 m for some versions). This limits the distance from the sensor pocket installation point to the valve.
Main AVTB applications
Because of its autonomy, the AVTB series is most often chosen in the B2B sector for two main tasks:
- Return temperature limiter in DH networks: Installed in the primary circuit of a heat substation, it prevents water that is too hot from being returned to the network, thereby ensuring the efficiency of the whole network.
- DHW preparation for a storage boiler: Acts as a primary heat transfer medium flow regulator, maintaining a stable domestic hot water temperature in the heater.
AVTB, AVTA and market alternatives
When designing HVAC automation, it is necessary to distinguish precisely the functional purposes of valves:
- Danfoss AVTA: A reverse-acting valve (opens as the temperature rises), so it is intended exclusively for cooling systems.
- IMI TA-Thermic: These valves are specialised for DHW circulation lines, ensuring balancing and maintaining the required temperature in risers.
- ESBE VTA/VTC series: Used for mixing flows (e.g. protecting solid-fuel boilers or preparing water for underfloor heating).
- Herz Calis-TS: A three-way thermostatic valve for distributing or mixing flows.
Frequently asked questions (FAQ)
When is it worth choosing an AVTB without electric control instead of an electric actuator?
Such a valve is the optimal choice for simple storage heater systems or for limiting the return temperature where there is no complex controller or where running additional cables is not desired. It ensures high reliability and requires no investment in electric actuators.
How do I assemble the unit correctly and select the sensor?
The final solution always consists of a valve body and a thermostatic sensor. The sensor is selected according to the temperature to be maintained (0-30°C, 20-60°C or 30-100°C). During design the 2 m capillary length must be taken into account, so that it is enough to connect the pocket to the control valve body.
Looking for reliable fittings for your projects? In our range you will find not only self-acting control without electricity but also industrial safety valves and other components. Contact the Amegata specialists - we will help you select valve bodies, sensors and capillaries precisely to your technical specification.