RE: multi-zone central heating

["Ward, David" <DAvid.Ward@xxxxxxxxxx>]

The cost of all these systems makes me keep coming back to a TRV with the
thermostat bit replaced with a simple RC servo and cam.
It would need minimal engineering, simple metal bracket with suitable cover
for neatness.
Te servo gives you the proportional control from three wires, add a
microcontroller and it can be neworkable...

Of course this assumes that the standard TRV (valve bit) gives a flow
roughly proportional to the position of the actuator :-S

Dave

-----Original Message-----
From: Kevin Hawkins [mailto:lists@xxxxxxx]
Sent: 21 January 2005 13:06
To: ukha_d@xxxxxxx
Subject: Re: [ukha_d] multi-zone central heating



Because when I open my current zone valves the inrush of hot=20
water heats=20
my cast iron radiators up and they retain too much heat - causing a=20=20
significant overshoot in the room temperature. so my room temp is=20
oscillating quite wildly - by some 4 degrees. ( I guess in your analogy=20
the capacitor value is too large and the voltage applied too=20
high ).   I=20
am also considering getting a better flow temperatue control=20
but that is=20
problematic too. Although  I do have boiler modulation control I have=20
some (cold) rooms that can generate a demand for heat from time - and=20
they need a high flow temp to warm them up quickly.    I sure Smart=20
Kontrols would sort it for =A325K   ;-)

Ake Hedman wrote:

>Kevin,
>
>but why do you need linear control. Isn't it enough with=20
open/close and=20
>control room temp. using the derivate of the actual=20
temperature. If you=20
>think of the radiator as capacitor this will work much the same as
PWM=20
>in electronics and give "sort of" the same result energy
wise.
>
>/Ake
>
>=20=20
>




=20