"Lurch" wrote in message
...
On Sat, 20 Nov 2004 23:42:14 +0000 (UTC), "Keith G. Powell"
strung together this:

This operation appears to be the same as my 1980s bungalow CH which it is
not a gravity system. It is fully pumped.

Below the thermostat set temperature, the 2- port valve is open, so water
is
pumped to both radiators and the DHW coil.

When the thermostat set temperature is reached, the 2-port valve is
closed,
so water is pumped to the DHW coil only.

That is the pump runs continuously. After the pump, the pipe Tees off to
the
2-port valve and to the DHW coil(via a stop cock).

The DHW cylinder does not have a thermostat.

The timer also allows either DHW or DHW with CH or both off.


That's not fully pumped, that's some lame attempt at plumbing.

Why is "my" system not fully pumped? Both the CH and DHW circuits are
pumped. No gravity/convection circuits involved.


It's a cobbled together hybrid system and should be discounted from any
country wide energy efficiency and heating type surveys.

I illustrated "my" system to show one reason why a pump would be running
continuously - not to advocate it. I make no claims about efficiency. But if
a survey was held about efficiency of installed systems, and it was ignored,
it would be a misleading survey. Besides, all systems are not 100% energy
efficient.

Yes, it could be more efficient - just by adding a DHW cylinder thermostsat
and a bypass and a bit more wiring, etc, etc. But that was not my point.

Keith G. Powell