Graeme wrote in message ...
Still sort of OT, where would you tap my cylinder to put in a flange? Top
(flat) or side?


If it's an Essex flange, a few inches down the side 6"? If it's a Surrey
flange, at the top. Yes it's possible to exceed the flow rate through the HW
tank when pumping. This can be alleviated by using separate 28mm feeds for
hot and cold supplies from the roof tank through to the pump where possible.
Using both Essex and Surrey flanges on the hot tank also helps at high flow
rates or the pump may cavitate. A big loft tank 100+ gallons helps. (Big
showers use over 3 gallons/minute) Ensure that all stop valves are fully
openable! Mount pump as low as possible to get the best gravity fed flow
rate into the pump.

Regards
Capitol