Re: multi-zone central heating

[Ake Hedman <akhe@xxxxxxxxxxxxx>]

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
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Ake Hedman (YAP - Yet Another Programmer)
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Kevin Hawkins wrote:

> Does anyone know of a reasonable cost 'proportional' valve in this
> format (attach to radiator)  - one where say 0-10V will provide linear
> control from closed to open ? Or failing that where a timed
application
> of a voltage will open a valve a certain degree and it will stay
there.
>
> Kevin
>
> Neil Ball wrote:
>
> >These type of actuators are commonly found on underfloor
heating=20
> manifolds.
> >They do take a while to open & close which is not a problem
with UFH=20
> due to
> >it's relatively slow thermal response. Biggest benefit is ease
of=20
> wiring and
> >low cost compared to motor-based actuators. If you are thinking of
using
> >them on radiator TRV valve bodies just make sure you get the right
torqu=
e
> >rating as too high a closing force will damage the soft valve
seats very
> >quickly and stop the valve from shutting off.
> >
> >Neil B.
> >-----Original Message-----
> >From: William Sadler [mailto:ukhad@xxxxxxx]
> >Sent: Thursday, January 20, 2005 17:43
> >To: ukha_d@xxxxxxx
> >Subject: Re: [ukha_d] multi-zone central heating
> >
> >
> >
> >On the same theme, has any body used these: Thermo-Hydraulic
> >Actuators?
> >
> ><http://www.danfoss-randall.co.uk/Site/downloads/VDSAP112.pdf>
> >
> >Which from the online page can be used to replace thermostatic
> >radiator valve heads and controlled electrically with 230 or 24
> >volts.
> >
> >William.
> >
> >
> >
> >=20
> >
>
>
>
>
>
>
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