"MP" wrote in message
...
Hi Bigwallop

Is the cold water feed into the hot water tank a dedicated feed? (so I
won't
get scolded if someone turns on a cold water tap elsewhere in the house).

snipped

The hot water tank is being fed from one single line of pipework. This
single line of pipework is cold. It's only when the water sits in the hot
water tank that you begin to heat it. Does you cold water storage tank get
hot? I should hope not.

The supply pipe to the hot water cylinder is large enough, if made 22 mm
dia' pipe, to supply both the cold feed to the pump and still have plenty
water left over to keep the hot water tank replenished and supply a hot feed
to the pump as well.

Two things. Is the cold supply to the hot water cylinder quite a straight
run down? And does the hot water run out of the bath taps at a much lower
rate than cold? I'm not talking pressure wise here, I mean at a very much
slower rate (quantity per) than the cold.

These can be checked by timing the filling of a large pot or bucket. From
empty, turn on the cold tap and fill it up. From empty again, turn on the
hot tap and fill it up. Deduct the times from each. If there is a huge
difference, and I can't there being, then you'll need to supply a pump from
two totally separate hot and cold supplies. If there is only a couple of
seconds difference, then you're OK to tap in to the cold and hot pipework
right beside the hot tank.

I was going to go all technical, but this explanation should be OK to
understand.

Don't over engineer it, you'll only **** it up. :-)