Dave Fawthrop wrote:

I took into account my atypical requirements and note the abundance of high
output combi boilers available for those with larger properties and less
insulation. The SEDBUK list gives 7 boilers at over 40kw, which should
cover any domestic requirement.

It was this sort of statement that used to land IMM in hot water, since
it assumes one size fits all and ignores many real world situations.

You assume the cold main can supply that rate - often it can't. You
assume that there is no requirement for simultaneous use (i.e. bath +
shower or two showers etc), you assume the shower is not of an elaborate
body jet or soaker head type that requires high flow rates, you ignore
that continously variable temperature output of any instantaneous water
heater that has to cope with variable flow demands, you ignore the cases
where insufficent capacity reamins on the 60kW rated gas supply. You
ignore those users with unreliable water supplies.

Need we go on?

Combis "out of the box"[1] are well suited to some lifestyles and
properties - not all.

gives 22 L/min DHW which should be enough for
anybody

Just like 640K huh? ;-)


[1] nothing stopping you from using a combi to heat a hot water cylinder
if required, and using that for bath filling etc.

--
Cheers,

John.

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