Here’s what an HVAC veteran has to say about electric actuators

Three components of an electric actuator

The first component is the temperature controller. In an electric heating actuator, the “electric heating” refers specifically to this part. Its operating principle is quite simple: when electricity is applied, it generates heat. It also serves another function—providing spring-return force, similar to a thermostatic valve.

The second component is the temperature sensor (valve actuator). The quality of an electric heating actuator largely depends on this part. Nowadays, reputable brands typically use imported temperature sensors, which require high manufacturing precision. As everyone knows, when heated, the sensor expands and drives the third component into action.

The third component is the actuator itself. The temperature bulb pushes it into action, and it then presses against the valve stem of the manifold. Looking at these components, you can see that for an electric actuator to go from being powered on to activating, the coil must first heat up, then the temperature bulb must expand, and only then can the actuator move. This is why electric actuators require a few minutes to activate. Some might ask, “Why make it so complicated? Wouldn’t it be better to use a standard solenoid valve that activates immediately upon energization?” This brings us to the issue of water hammer. If the valve were to activate instantly, the water flow would change abruptly. The inertia of the water flow would create a shock to the system, potentially damaging components—much like the difference between slamming on the brakes and braking gently while driving.