On Tue, 14 Sep 2004 21:35:11 +0100, Andy Hall
wrote:


That would be making the assumption that the water reaches 60 degrees.

Combis are quoted with a flow rate based on a temperature rise of 35
or sometimes 30 degrees. Therefore, the quoted rate will only be
achieved when the water going in is at 25 degrees or more. This is
way over-optimistic and only achieved in long periods of hot weather.

In the winter, water temperature averages 5-8 degrees so at the stated
flow rate, water coming out will be at shower temperature.

The relationships are all linear.......

I see, maybe that's where the IMM concept of 2 boilers comes in, there
is an extra one hidden in the attic to boost the DHW

I reckon most people could wait an extra 5 mins for the bath to fill,
I'd be tempted to get in when the bath is half full.

Also for a larger 40kW combi 16l/min at 35°C should be enough for a
decent shower.

cheers,
Pete.