"Pete C" wrote in message
...
On Sat, 25 Sep 2004 15:18:38 +0100, "IMM" wrote:

Hi,

Would that only be OK for a vented system?

Yes. Just have a stadard CH F&E tank top the heat bank up.

What pressures can sealed
systems

Sealed systems operate at approx 1.5 to 2 bar and a max of 3.5 bar, the
blow-off setting.

and direct cylinders operate at?

There is grade 1, 2 and 3, with grade 1 being the highest.

Grade 1 cylinders, the highest pressure are rated at 2.5 bar working
pressure and a test pressure 1 bar above that.

Oops, meant using a cylinder with a sealed system, but that answers my
question.

If you have a sealed boiler/CH system and want a DHW only heat bank, you can
use a cylinder with a quick recovery coil. You will still need the F&E tank
to top up the heat bank, or use a combination cylinder if you want an all in
one solution. Extra tappings, exactly where you want them, can be inserted
by the supplier/maker, usually for free, or a slight extra charge.

Also I wonder if it's possible to put a blending valve in so that
primary water from the boiler is used by preference, with water from
the heat bank used when necessary.

I don't quite get you. Best let the boiler heat the cylinder using a
blending valve on the flow/return, that only alows 75-80C water enter the
top of then cylinder. Heats up top down.

True, sounds good.

If having a condensing boiler and quick recovery cylinder then you can
dispense with the blending valve.