Does anyone know whether there is any manual control on the OEM version
of the Alpha pump fitted to my 30CDi system boiler? It is supposed to
be a modulating pump but it does not appear to change speed at all as
the TRVs close and I can't decide whether it is just faulty or whether
it is not set up right or matched to my system.

I had a WB engineer look at it and he changed the pump head and system
board - no improvement. Is it possible that the sensor/control gear was
not changed by this and a fault still exists? In defence of the
engineer he had been given no information about this pump.

When most of the TRVs are closed the high flow speed causes a lot of
noise in the lounge rads. I know there is a lot of 25mm copper in the
circuit and also wondered whether this gave low resistance and, even
with a lot of closed TRVs, meant that the pump was not reducing speed.

I have another WB engineer calling tomorrow but would like to know if
there is any experience out there that might help diagnose the problem.

By the way, the pump is marked Grundfos Alpha, DDWPM 15-60 and UPER
XX-60 J2 and does not appear to have the setting control that is on the
standard Alpha pumps.