On Thu, 23 Sep 2004 12:28:20 +0100, "IMM" wrote:

Gledhill do not have a flow switch. They use a temp senor on the DHW
draw-off that times the rate of temp change and modulates the pump to suit
to maintain a DHW draw-off temp of 55C. If low flows a low pump speed.

Sounds like a DIY electronics project in there.

That is why it is best to have a
hybrid heat bank: a coil and a plate heat exchanger. The coil for low flow
rates, where no pump operates and the plate with pump for high flowrate.
Only when high DHW flows will the pump and plate cut in. The coil also acts
as a pre-heat to give higher flows in winter when the mains water may be
colder, although a correctly sized plate would make no difference.

Could an immersion cylinder be used as a heat bank?

cheers,
Pete.