"Pete C" wrote in message
...
On Sat, 4 Sep 2004 21:53:07 +0100, "IMM" wrote:

It is. Even a modulating boiler cycles when demand is below the minimum
kW.
With a heat bank, no cycling.
Hi,

How much heat is lost when a modulating condensing boiler cycles? Not
much I would have thought, as the heat exchanger probably has low
thermal mass and operates at a lower temperature.

The controls can take a battering, raising the likelihood of breakdown.

Another way of doing it would be to
connect the lower half of the heat
bank/thermal store in line with a differential
bypass valve and 2 port
valve in parallel.

Then as the system gets up to temperature
and the TRVs close, the
thermal store would take the excess heat.
When that reaches
temperature and the burner switches
off, the 2 port valve would open
to release the heat back into the system.

I'm not sure if I'm with you. A buffer to take excess heat. Fine. Heat
from where? A better description of the pipe layout would be nice.