Mike wrote:

He basically said that the system is a poor design, with a low powered
boiler (which is probably fair point, the maximum flow seems to be 80c
where as the tank wants to be 75c so there is not much redundancy
there). So its running at full kilt.

I thought most boilers (bad name I know) tended to max out at around 80c
or so - or at least, their thermostat turns the burner off at that
point. Do boilers really go above that temp?

D