To find out whether your radiator's hydraulic valve is thermostatically controlled, you can refer to the following pictures.
In the first illustration, right, we have reproduced a classic example of a non-thermostatic valve. This is a valve in which the water flow can only be managed manually, as if it were a tap that can simply open/close the water flow in the radiator. Generally, manual valves have a central screw, as in the enlarged image, and the knob may not be removable.
On the left of the illustration we have a classic example of a thermostatic valve: by removing or unscrewing the knob, a small spring pin can be seen in the centre, which can be pushed into the valve body and it is this that regulates the flow of water in the radiator.
Below are the illustrations of:
- a manual thermostatic valve
- removing the plastic cap of a thermostatic valve