Pressure reduction valve?

[angefoh]

OK I still have an issue with my cold water inlet to my hot water tank. There is a series of valves (see picture) and the meter is showing nearly 9 bars of pressure. I have turned of the water supply and ran hot and cold taps but this meter is not moving. I have tapped it and it does not seem to be stuck. The hot water is running normally . I do not understand what is happening or what these valves do.

 

[ShaunCorbs]

Time to get a qualified plumber in

Do you know anyone local (Germany)

 

[angefoh]

OK I was trying to avoid the local plumber thing.
How do you know I am in Germany?
And no I don't know anyone local.

 

[Harvest Fields]

Ohhh. Now that is a secret. But as above. You need a proper engineer to sort it for you.

 

[angefoh]

OK so the problem occurred when I think a mixer tap valve failed and I had cold water of the mains flowing into the hot water side of the boiler.
So I will not attempt to fix this myself I am just curious as to what could have happened and what these valves do?

 

[Riley]

They keep the safety features of your water tank in check

 

[ShaunCorbs]

german writing on the top of the right hand grey knurl

 

[Riley]

Oh he’s good

 

[townfanjon]

Nice to see us friendly English chaps trying to help out one of our European friends , more than the eu lot helping us.

 

[angefoh]

Actually I am English

 

[angefoh]

OK I thank each and all for the helpful and not so helpful comments.