Re: automated baths

["Campbell Macdonald" <c.macd@xxxxxxx>]

Looking at the mixers I have (I think this is normally the case)...... the
mixing occurs after the main tap shut off.......there is no possiblity of
feedback from cold to hot (as free flow will always be into the bath). Even
if the electric valves were to fail open....then the system would just
operate as normal, with the mixer stopping or allowing flow.

If you are using a hose which can be shut off at the hose end, then there
is
a possibility of flow back through the hose, if mains is off or broken, in
this case you will need a nrv.


Campbell

----- Original Message -----
From: "Phil Harris" <phil@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Thursday, November 13, 2003 11:18 AM
Subject: RE: [ukha_d] automated baths


>
> > "Automated filler" = solenoid valve downstream of a
thermostatic
> > mixer valve (you'd have to pre-set the temperature that you want
> > your bath). You could have the temperature specified on a
> > case-by-case basis but it does get more complex.
>
> You would also need to ensure that there were non-return valves on the
hot
> and cold suplies to the mixer so that when the output was closed you
don't
> get the possibility of mains pressure cold water backflowing into the
hot
> water tank...
>
> > 40mm solenoid valves are available, but usually reserved for
> > industrial applications (read: expensive). You may want to
> > consider multiple 15mm solenoid valves on the drain to ensure the
> > bath doesn't take all evening to empty :-)
>
> www.laser.com have 40mm "Toro" valves listed on their site
IIRC - I was
> going to use them to do an automated bog flush ("dump
valve"? ;-) ) but
> wifey won't let me.
>
> Phil
>
>
>
> UKHA 2004: 15th and 16th May 2004
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