Try to find the data sheet of it at Aquamedic.. It'll explain the numbers on the label and it might also reveal the max working temperatur..
Approaching the label with a bit logic and usual standards i think it stands for
NW 2,3 mm coupling for 0 - 4 bar presure
AC 230 volt / Ambient temp range 50°- 60° C
ED 100% = ED = (German) Einschaltdauer = Switched on timespan or Duty Cycle
Power consumption 2,5 watt
100% Duty cycle refers to the duty cycle of the relay function and stands for it should be able to continuesly switched on without overheating. Suposse it says 50% you would need 1 hour off time / cooling after 1 hour on time / heating.
Ambient temp range stands for the max allowed temp of the invironment the device is in and still be ED 100%.. This is 60°C, pretty hot actualy.
So the unsulating casing is pretty temp resistant probably exeding the 60°C. because if the ambient temp already is that high the casing will be a bit warmer since it takes on ambient temp and some temp of the coil added.. It also means that if you place the device in a small closed invironment with little ventilation the device itself will warm up the invironment and the device will get warmer as the ambient temp gets warmer. So the working temp of the device is very depended on the ambient temp that's why it is often not specified in the technical data sheet. But sometimes it is, you have to look that up if you can't find it ask aquamedic they should have it..
Anyway 60°C is acceptable.. This is pretty hot and will not feel comfortable touching it.
Check for example the temperature in the cabinet where it is in.. If this is rather warm because of all th electrical equipment running in it. Than the solenoid has little cooling and can get pretty warm as well, making the space in the cabinent even warmer again..
