"Andy Hall" wrote in message
...
On Wed, 1 Sep 2004 22:49:17 +0100, "IMM" wrote:


"Dave" wrote in message
...
Thanks to all for the responses.
It looks like the answer is a Worcester Greenstar

Good choice.

running vented into a
direct heatbank

Sounds good.

with a zone
valve for the rads

One zone valve for the radiators
and a second for the heatbank would
be the most appropriate, or a diverter valve.

Located where?

Errm no. The rads taken off the heat bank using a pump and a check
valve.

This is not the best way to connect the radiators.

Oh my God. It is the best way.

Apart from needing
an extra pump, it is not the most
efficient way for the boiler to
work.

What the hell are you on about?

For the heatbank to be useful,
it needs to operate at the highest
temperature possible in order to
store the maximum amount of energy.
This is true throughout the year.
The minimum useful flow
temperature to the heatbank is 75 degrees,
with 82 being better.

You split the cylinder with a flow and return on the upper DHW section and a
flow and return on the lower heating section. The lower section can run at
a lower temp than the upper. Best use an outside weather compensator and
have the temp senor on the lower cylinder section. Both sections only need
a pump and check valve each from the boiler, with the DHW having priority.
The compensator will ensure the rad circuits will run at low temperatures
most of the time promoting condensing efficiency.

For the condensing boiler to run most
efficiently

snip

see above.