"Christian McArdle" wrote in message
t...

Arrange the system so that the boilers
output is combined with the heat
banks and a greater flowrate with a
smaller cylinder

It is an indirect coil, so it won't have this
ability. It needed to be indirect, because
I needed a pressurised sealed CH circuit,
which obviously isn't possible with a direct
cylinder with atmospheric pressure water.

That doesn't make any difference. Put a 3-way diverter valve on the flow
from the boiler to the coil of the cylinder, and take a pipe from one port
to another plate heat exchanger. Have the cold water coming into the
boilers plate and then out into the heat banks plate.

The outputs are combined. The heat bank assists the boilers output, which
will be at full belt. This way the stored water is kept long. When the
heat bank runs out of hot water an electronic quick acting pipe stat with an
insert pocket will cut out the heat banks plate heat exchanger pump
preventing the cool heat bank water cooling the boiler heated water, then
only the boiler will provide DHW, meaning you can never run out of DHW
whatsoever. When there is no flow the boiler immediately starts to re-heat
the heat bank. The boiler should be full on and the heat bank will top up
the shortfall. This way you will get around an extra 10-11 litres per
minute of flowrate, never run out of hot water and a smaller cylinder can be
used.

There is also backup in case the heat banks DHW pump fails. All for the cost
of a plate heat exchanger, pipe stat and a 3-way valve. You have to arrange
the control system of course.

BTW, did DPS leave the CH tappings on the heat bank?

It is sized so I don't need to rely on
recovery for it to work. The sizes
only affect the height of the cylinder,
so there is no space implication in
going for a 180L instead of a 150L or
a 120L. It's going in the loft.




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