This summer we moved into 4 bed, 1 bathroom, 1 shower room house. As
we were about to renovate the place we decided to get the heating
system updated. We got the details of a local plumber who had the
necessary unvented heating certificate from the Institute of Plumbing.
He installed a 210lL unvented cylinder, a Potterton Surpima 100
boiler, replaced all the 9 radiators, and desclaed the system. We
advised him at the time that we may convert the loft at some point and
so needed some spare capacity in the system. We paid him over £6k for
this.

We have 2 problems.

The first is a knocking noise in the floor of the bathroom and the
bedroom closest to the bathroom. Not a loud banging but enough to
wake up anyone sleeping in there. It doesn't happen the whole time
the heating is on but isn't just when it's warming up. From reading
this forum, it seems one possible soultion could be that the pipes
aren't clipped down. If I get someone in to lift the floorboards will
it be obvious how and where to clip down the pipes? (DIY novice
clearly).

The second problem is that the rad at the end of the system (our
bedroom) doesn't get hot if all the other rads are on. I believe this
could be the pump size or boiler size. What size pump should I have?
The boiler is on the ground floor and the rad on the 2nd floor.

We've asked our IoP registered, corgi plumber back but he's claiming
it's nothing to do with him. He says the knocking is from the old
system and the rad doesn't heat up because of the pipe size or maybe
sludge in the system. He never mentioned pipe size when he was
fitting our boiler, rads and cylinder. And as replaced all rads and
rescaled the system I wouldn't expect any sludge.

Any advice much appreciated.

Victoria