"Andy Hall" wrote in message
...
On Mon, 14 Feb 2005 21:43:11 +0000, Doctor Evil
wrote:


the-moog Wrote:
This is another point of confusion for myself.

To take the CH and/or UFH from the store or the boiler circuit.
Obviously, to take it from the store means instant heating, but
depletes our DHW source.
The other way means that we are 'steeling' heat from the input to the
store, so it will take longer to replenish.

Any other factors in deciding which side the heating should come from?

The only thing I can think of is the need for more than one pump.

J.

Take it from the store. If the store is sized well enough it will not
deplete the store. Also the CH flow and return are taken near the
bottom, leaving the upper DHW untouched. You could have it a priority
system. Wheh the DHW is called the CH pump(s) is switched off. The
boiler operates independently heating the store of water to a
pre-defined temperature. Have two stats on the heat bank so as to
avoid boiler cycling. Have the largest boiler you can afford. A
therml store/heat bank is not fussy what sized boiler heats it. Make
sure the flow and return pipes are 28mm.

Two CH zones: Either:

1. Two pumps (both directly off the store)
2. One pump and two 2-port valves. (only one pipe off the store)

Taking all zones directly off the store eliminates a balancing act
between two zones.

This is misinformation if a modulating condensing boiler is used.

Not in the least. Many modulate on the flow temp (maintain a constant flow
temp). Those that modulate on load compensation will modulate down when the
return and flow temps narrow down.




_________________________________________
Usenet Zone Free Binaries Usenet Server
More than 120,000 groups
Unlimited download
http://www.usenetzone.com to open account