This is my first post here as you probably can guess. Basically I have a Vaillant boiler which doesn't state a model name although it does show a code (80 92 26GB 02). I am having a problem where the shower hot water is scalding hot and although I am turning the temp knob down it didn't seem to be making any change to the hot water temp. After looking a bit closer the knob is turning but gets right to the end of the screw thread then comes off.
Now, there is a bolt and in the middle of that (where the screw screws into) is a brass fitting. Am I right in saying that this brass fitting should turn therefore turn the hot water temp up or down? I have tried turning it with pliers but it just seems to start turning the bolt instead. Any help would be greatly received as I am getting scalded not from the water but from the mrs :)