Hi Bob
On (19 May 96) Bob Knowles wrote to Alec Cameron...
 BK> I have always fancied hot water pipe under floor heating with
 BK> thermosyphon but I have a hot water boiler with a small pump that uses
 BK> so little power that I leave it on all winter without switching it on
 BK> demand.
I was involved with electric underfloor heating, at some power stations
[admin offices, locker rooms, shower rooms]. The thermal inertia/ long 
hermal
time constant was sometimes a horror, a change in ambient temp would be
accompanied by very long heat up- cool down periods. Staff grumbled.
Even more serious, elec shocks to the bathers! Not easy to achieve perfect
grounding inside a PS that deals in huge load currents.
My personal [human] thermostat is very dodgy and I want rapid response to my
needs so our house has flued natural gas at one end and reverse cycle split
sytem at the other.
 BK> For anyone who does not understand 2 and 4 pipe systems, 2 pipe is a
 BK> flow and return that uses hot water in winter and chilled water in
 BK> summer. The same coils are used for both applications (heating and
 BK> cooling) The 4 pipe systen has 2 flows and 2 returns. A flow and return
 BK> for the hot water and a flow and return for the chilled water. The 4
 BK> pipe system need a heating and a cooling pump. It also needs a  heating
 BK> and a cooling coil  in each fan coil unit.
And you have independent thermostats in each room to adjust the local flow
rate, yes?
Cheers..ALEC   ps 2.5 deg outside, at breakfast today.
... ........The best carpenters make the least chips
--- PPoint 1.92
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