Stadler WD23 Radiant Heating Controls, unable to adjust temperature

I have radiant heating at home in the main floor areas, installed probably in 1996. I find that the house gets quite cold and need to adjust the temperature upwards. However, I dont have the manual and dont know how to do it. I did not want to just mess around with the controls without knowing. If anyone can provide manuals or direct me to how I could get them, would much appreciate. Also if someone can instruct me on how to adjust the temp upwards, would help me. Pics of my system are attached.

Secondly, I am looking to replace/ upgrade the control system, would much appreciate suggestions on this as well.

Much thanks for your help