On 21/05/2017 13:49, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
A modern unvented cylinder will have a much larger coil that can take
heat at 20kW plus. That means you can direct the full output of the
boiler at it. Hence its better suited to W or S plan style control
systems (unless you have a very powerful boiler) but no heating while
its recharging.


I have what was known as a fast recovery cylinder which stores my hot
water. I dunno what the maximum transfer rate is, but it is enough to
provide a warm shower constantly. Ie, starting out from cold, as I
discovered on coming back from holiday some years back, and wanted a
shower before going out again - I was willing to risk a cold one. ;-)


Mine is about 16kw nominally, but it depends on what temp you set the
flow on the boiler to and what temp you set the tank to, so its not an
easy thing to compare.
The system can keep up with the shower unless you turn on the big
overhead one which at something like 24l/minute is a bit too much.
It takes a while for you to notice as there is 120l of hot to go through
first.