Michael Kilpatrick wrote:
On 25/04/2012 22:26, John Rumm wrote:

Also don't ignore the possibility of using one combi to heat a cylinder
of water as well as being able to provide hot water on demand itself.

This is exactly what I specified for our extension, and was surprised
when the plumber said that it was a little unusual.

the cost of a combi and tank exceeds the cost of a system boiler and
tank really so its a waste of money with no advantages

The general rule is the money you have a tank dont have a combi: they
are a cheap low footprint abortion suitable for CH and one-at-a-time hot
water and if they are to given a decent hot water flow-rate more
expensive than a sealed tank and system boiler