Hot water temperatures at the basin

[ShaunCorbs]

Prior to the solar the temperature was controlled by the boiler setting and how long you ran it for. With the solar it is constantly heating.

that’s bad as your not fully heating the store and bacteria could grow

 

[Ric2013]

I can see where the OP is coming from in that he or she used to be able to control how long the boiler was run for, like my grandmother who used to turn her immersion heater on for just half an hour. As ShaunCorbs has said, this method would result in the cylinder not being fully heated through and is bad practice. It's a bit like leaving the gas oven door open to warm the kitchen - effective, but you do it at your own risk and in breach of the manufacturer's instructions.

I can see why the OP is disappointed - he or she never presumably had formal instructions for the old system and so would not have realised that being able to control the temperature in this way is actually not a good idea. The correct way to use a stored hot water system is to heat the cylinder till it is hot through (and even if you don't maintain that temperature constantly at least you will have reached it for long enough to pasteurise the water), but if no-one tells you, you won't know.

On a more sceptical note, can anyone explain to me why water from a cylinder and that from a combi boiler are treated differently by the regulations? While I understand the combi boiler does not store water and thus bacterial growth in storage is not possible, I can't really see the technical difference between storing water at 60°C and blending it down at the cylinder outlet (which most of us will probably agree is not compliant) and water leaving a combi boiler at 40°C and running through the pipework at that temperature (which most of us will probably agree the Water Regulations seem to begrudgingly accept).