Thanks to you also.
I thought there was a blending valve fitted in the boiler. maybe I am wrong?
If not then what do I need and how do I ask someone to fit it correctly.
Thanks for the reply.
I am not a plumber - I work in an office.
I measured cold in to the boiler >25 l/min
and hot out <12 l / min
Understand the issue over resistance but surely this could not reduce the flow by more than half (the pipe run between the 2 is less than 1 metre). Both...
I agree with Simon. I have had a 937 now for 4 years and it has always performed badly. I have had vaillant out a number of times and a number of plumbers look at it. Until last week I was given every reason under the sun as to why it was not working - gas pressure, pipe size in the house etc...