RE: Replacing and automating the Central Heating switch (PIC fixed)

["Mike Griffiths" <mike@xxxxxxxxxxxx>]

That could work Gareth but I think it is safer to keep mains
associated
with the boiler in the boiler

Running a control to the boiler is the best bet



Imagine you go back to the relay unit in two years looking for a fault

You isolate the mains feed to the cbus relay unit assuming it is then
safe to work on

Forgetting the "other" mains feed coming in from the boiler

Your HA system isn't calling for heat

So when you test for live mains there isn't any



Half way through your fault finding the HA system calls for heat



As you lie on the floor shaking you remember the mains coming in from
the boiler you ran 2 years ago



OR

You could just put a big message on the dimmer ;-)



My 2d worth

Mike



________________________________

From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
Of Gareth Cook
Sent: 02 February 2006 09:19
To: ukha_d@xxxxxxx
Subject: Fw: [ukha_d] Replacing and automating the Central Heating
switch (PIC fixed)



Or

I could install a 2-way light switch between the feed to the old timer
and
cbus, and the feed to the boiler. So when switched one way, CBUS
controls
feed. When the boiler man arrives, flick the switch and the old timer
module now controls the feed.

Sounds plausable...

G.

Gareth Cook
Tools and Process Architect
IBM SWG Sales - Lotus Park, Staines, TW18 3AG
Office: +44 (0)1784 445166 - Mobile: +44 (0)7980 445166
AIM Chat : TheBoyG - MSN Chat : chat@xxxxxxx
email: g@xxxxxxx


----- Forwarded by Gareth Cook/UK/IBM on 02/02/2006 08:58 -----

Discussion
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ukha_d@xxxxxxx
Today 00:28

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Subject:
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RE: [ukha_d] Replacing and automating the Central Heating switch (PIC
fixed)
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Category:



That works!

What I have done is put a relay from the Timer output to the boiler

Then I run the timer to always be on

The relay the says when it is off via in my case HomeVision



The advantage of this is I then have a test mode where the relay is
always on



So if  any one comes to fix the boiler

Put it into test mode and as far as they are concerned it is a normal
control system they are used to



I have a 12v 2 mains relay in the boiler

That way nothing control wise leaves the enclosure

Far better that running mains from the boiler to the C-bus relay and
back again

If that isn't clear give me a bell or mail

Mike









http://tinyurl.com/bqo3r

G.
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