DIY Doctor UK DIY Forums

Hi Everyone,

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 :)

Hi.
From your description it,s the shower valve that's the problem, rather than the boiler. Can you supply some more information on the valve, make, model, etc. A photo maybe.

I agree with protech - test the other hot taps around the house and if there all scalding hot then chances are it might be the boiler. But i would focus on the shower valve.

Had same problem and it was the actual facing board of the shower unit which needed to be replaced because the cogs to adjust the temperature were worn or simply not engaging. No problem with the actual central heating boiler .