RE: multi-zone central heating

["Neil Ball" <neilball@xxxxxxxxxxxxxxx>]

Re smartkontrols - we probably could ;-)
=20
However, the smartkontrols Intelligent Actuator is not a 0-10v device it is
an raise/lower actuator that positions itself based on the percentage of
travel time required and then the position is fine tuned based on actual
room temp feedback. For example if it needs to open to 50% then it runs the
motor open for 50% of the total stroke time. Another control method is
time-proportioning control as mentioned by Ake. When the rooms are cold you
leave the radiator valve fully open, but as you approach setpoint you start
shutting the valve for longer and longer periods. Both methods give you a
form of modulating control from open/close type devices, but both
approache=
s
require processing and feedback to work well.
=20
HTH
=20
Neil B.
-----Original Message-----
From: Kevin Hawkins [mailto:lists@xxxxxxx]=20
Sent: Friday, January 21, 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 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 high ).   I=20
am also considering getting a better flow temperatue control 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 open/close
and=20
>control room temp. using the derivate of the actual 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
>



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