"Bolted" wrote in message
...
Doctor Drivel wrote:
If it is not possible to get a good flow, then I would fit an
accumulator. You can make one yourself for a fraction of the price what
some people are selling them as packages.

Could you explaining how to go about making one? I might have to fit one
if the water main replacement doesn't do the trick for our rubbish flow
rate, and they appear to be ferociously expensive in off-the-shelf form.

The Reliance 200L accumulator is ~£300.
http://www.rwc.co.uk/Product.aspx?page=CAT6
No. 2.

So the controls and all can be fitted for a fraction of the price of the
Dual Stream (link below). About £400 inc controls for a 200 litre which
effectively will store about 100 litres of cold water, which is fine for a
one bathroom house. It gives the static mains pressure but lots of volume.
If the mains is cut off there is a store of cold water.

I would say minimum 1 bar mains pressure to operate and a pressure relief
valve.

You need on the mains pipe.

A double check valve on the mains
pressure reducing valve set to what Reliance recommend (maybe around 3-3.5
bar)
line strainer
Full bore maintap
Pressure relief valve set above the PRV
tundish

If using a heat bank then that will be OK. If the cold is supplying a volume
of water that will be heated (unvented cylinder), then a double check valve
on the cylinder supply.

Some Reliance accumulator models may have the diaphragms replaced too.
Look at this to give an idea of where components fit:
http://www.gah.co.uk/GAH_Dualstream/frameset.htm