What is Thermal Actuator?


Brief description

Thermal actuator is a two-point drive device, connected to a controller with a two-point output end, such as a room temperature controller, a hygrostat , a floor heating remote control system, a room thermostat and is a new type of actuator used to control the flow and heat of the terminal device.

Thermal actuators are widely used in floor and ceiling radiant heating and cooling systems, air conditioning systems, radiator heating systems, and other systems that require temperature control or fluid on-off control. Thermal actuators should be used in conjunction with regulating valves.Thermal actuators are divided into normally open type (Normally Open) and normally closed type (Normally Closed). Normally open type means that the regulating valve controlled by the actuator is in the open state when there is no power, and is closed when power is on. On the contrary, it is normally closed. In the heating system, both normally closed and normally open types can be used, but in the event of an unexpected power outage, if the water in the pipe freezes due to a drop in temperature, the accumulated expansion will damage the pipe system. In the air conditioning system, normally closed actuators are usually used. So in this case, we developed and designed the 920062PL product, which has a manual opening and closing function. It can provide convenience in installation, and you can also choose to open or close the actuator when there is a power outage.

Working Principle

The operation of the thermal actuator is achieved through the thermal expansion and contraction of the temperature package. For the normally open electric actuator, when the working voltage is turned on, the temperature package of the actuator will be heated, and after the static time, the closing process will be evenly performed. When the voltage is interrupted, the temperature package gradually cools down, and after the static time, the actuator will open. The opposite is true for the normally closed actuator. From the working principle of the electric actuator, it can be seen that since the electric actuator is slow to open and close, it will not produce water hammer phenomenon, which will greatly extend the service life of the valve.

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There are some regulating valves on the market now, such as electric two-way valves, which have more or less mechanical, electrical or hydrodynamic problems. Compared with these regulating valves, our company's electric thermal actuators have many advantages:

Thermal actuators work by thermal expansion and contraction, have no mechanical transmission parts, and do not have any mechanical wear.

Electric thermal actuators complete operations very smoothly, avoiding the occurrence of "water hammer".

Compact size, especially suitable for installation in places with limited installation space such as central air-conditioning systems.

Functional inspection can be easily achieved through the position indicator (normally closed type)

No noise, maintenance-free.


Used in Floor heating systems

Thermal actuators are widely used in floor heating systems. Install a room thermostat in the room where the room temperature needs to be adjusted and connect the actuator to control the flow of the room circuit. When the room is large, several circuits may be required in the same room. In this case, one thermostat can be used to control these actuators in parallel.


Used as zone valves

In some occasions, a large area only needs to be controlled at one temperature, such as a conference room, business hall, or a room where the temperature of each room is not controlled separately. In this case, the thermal actuator and the regulating valve can be installed on the return water main of the manifold to control the temperature of the entire area. The following figure shows the installation of the electric actuator on a 3/4", 1" or 11/4" regulating valve, used as a zone valve.


Used in air conditioning systems

In air conditioning systems, the location of the terminal radiator is limited by space, so installation and construction are difficult. Electric actuators are small in size and not limited by space. They are suitable for both heating and air conditioning. They are a solution for air conditioning systems and can avoid many problems that may be encountered during installation and operation.


In the same room, or in areas where the room temperature requirements are basically the same, multiple actuators can share one thermostat.

For radiators

One of the most widely used places for electric actuator control is in public buildings, especially schools. A common problem encountered when using temperature control valves in schools is that the hand wheel or temperature control head is tampered with or damaged. The manifold and electric actuator method can solve this problem very well. Water is distributed through the manifold, and the manifold is placed in the manifold box that cannot be touched by people. On the heating pipe, ordinary temperature control valves and return water balancing valves are not used, but the built-in valve of the manifold is used to complete the balance and adjustment. The flow rate can be adjusted only at the manifold. The control of a single radiator is completed by an electric actuator installed on the manifold, and the actuator receives the opening or closing instructions from the controller to act.

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