"Pete C" wrote in message
...
On Tue, 21 Sep 2004 13:20:58 +0100, "IMM" wrote:


In that case you'd connect a DHW 'preheat' circuit across the
heatbank's primary water connections.

Possible. You could have a second plate heat exchanger on the flow
fromthe
boiler with the cold mains running though it.

It is better to have a
blending valve on the flow/return which ensures only 75-80C water enters
the
store at the top and stays there. The store heats up "top down" being
direct. As the DHW plate takes its heat from the top of the store you
gain
nothing by having a pre-heat plate on the flow.

Hi,

Sorry, by preheat I don't mean heating DHW before it reaches the heat
exchanger, just keeping the DHW hot in the pipes to save water and
have a quicker response when the hot tap/shower is turned on.

When the pump kicks in, heat is taken from the heat bank to the plate very
quickly giving an excellent response.

I was suggesting using a non DHW circuit alongside the DHW pipe and
separate pump connected to the heatbank to keep the DHW hot. Though as
a pump is used on the secondary side there might be a way of getting
it to do this too.

Read my post on this thread on this point using a pipe stat and secondary
bronze pump.