On Tue, 02 Nov 2004 16:10:39 +0000, Christian McArdle wrote:

Was there any particular reason you fed the rads directly from the
primary?

Yes, the radiators are (or will be when I convert the loft) the highest
point in the system. This means that they require a sealed pressurised
system. It is actually possible to have a " fed from the heat bank, but
this requires 2 additional pumps and an additional plate heat exchanger.
The boiler and cylinder are already in the loft and I didn't want
additional tanks above, even if they could have been accommodated
somehow.

OK... Sorry for being thick: The header tank's already in the roof and
it's staying there (3 ft above the highest rad).

I'd assumed that the thermal store water + boiler primary were generally
pressuried by the header tank (though I did notice that your Pandora is
locally filled through a little plug in the top of the cylinder, which I
hadn't expected?)

In other words, I though that the termal store system wasn't dissimilar to
the way that a conventional HW cylinder is pressurised by the CW tank in
the loft. So I hadn't actually foreseen a problem, as long as the rads
were below the header tank level.

Is this an area which thermal stores vary a lot in, and does "sealed
pressurised system" mean "fed from a header tank in the loft"?

Sorry again for sounding like a bit of a plank. :/

Timbo