Capitol wrote:
robgraham wrote:

cut

Using a low pressure booster pump as a panacea will not solve the
problem if it is elsewhere. The pump could in some cases give a head
below about 12' if mounted at bath floor level. Shower pumps normally
give heads of 20--80'.

This thread had lots of advice, some very poor due to inexperience
(dIMM) which probably would not solve the real problem.

I was the one who said he would keep the post. The point of using a
small quiet pump fitted in the pipe, possibly near the shower mixer,
not on the floor, with a mixer with a pressure equalizing valve using
the cold mains as the cold feed is very sound indeed. And very
appealling. Two have said they have already done it and it works and
that is good enough for me. This pump has 1/2" connections and is
unlikely to drag all the water out of the cylinder and only suitable
for one outlet point like a shower. It will suck out of the cylinder
and down the cold feed from the cold tank. If this is 22mm pipe then I
can't see a problem. If it doesn't work then you are right in that
there is a problem elsewhere, like a blockage. The only dim one on this
thread is you and you have a clear attitude problem.