"John Rumm" wrote in message
...
John Powell wrote:

One potential problem for me is the apparent low flow rate into the
house from the mains

I did a check at the nearest cold tap to the water inlet, ( the cold
water is at mains pressure) - I filled a 2 litre jug and timed it

it came out at about 15l/min

would that change the optimum choice of boiler?

I had this concern myself since we have a poor (ish) mains feed. I found
I actually got the best flow rate at the cold bath tap however (the
kitchen tap is a monobloc mixer with microbore feed, and was giving a
misleading impression that the feed was capable of 5 or more l/min less
than was actually the case). So it might be worth repeating the test at
another tap if possible. Use a larger container and time say 10 litres
to get a more accurate picture.

If the limit really is 15 l/min then you have three choices:-

1) live with it, since it is plenty good enough for a shower, and is not
going to restrict the performance of any combi below 38kW (i.e. quite
large)

2) Upgrade the mains feed

3) Fit a mains pressure unvented cylinder, and heat it like you would a
conventional hot water cylinder.

Option 2 is worth doing if you are looking for a very high end combi
system (or multiple combis).

Option 3 will outperform the combi
systems for things like bath filling

Not so. The Alpha CB50 combi will perform just the same. In fact it has an
unvented cyoidner inside it, and will revert to a,ow flowrate when the
cyinder is empty, which should be very rare in anormal one bathroom house.

but cost as much or more than IMM's
"a boiler for every room of the
house" scheme.

Nothing like a know-it-all amateur is there.