RE: Re: [OT] ishh central heating controls

["Dean Smith" <dean@xxxxxxxxxxxxxxx>]

I placed relays after the existing CH controller but before the
Thermostats.

When un-energised (?) these simply pass the existing controller signals
through. When energised they disconnect the original and pass 240V as
required.

The CH is therefore a DPST . The HW is a DPDT - and disconnects both HW-ON
and HW-OFF controls and gives 240V to HW-ON only so no matter what the
origianl controller was asking for - I can over-ride.

I ran it like this for some time using Comfort to control the relays for
+1Hr boosts ( Whether its was Via X10 or hard wired switches ) and the
orginal controller for timings. I have now moved all the timings to Comfort
aswell - the orginal controller is still there but I've cleared all the
settings. I could remove it totally so long as I hard wired the HW-OFF
which
is currenlty provided 24x7 by the controller.

http://www.eatworms.org.uk/ha/heating.php

My wiring
http://www.eatworms.org.uk/ha/heating1.gif

I would echo Patrick's comments though - dont mess unless you know
absolutely what you're doing. CH failure is an absolute killer of WAF !

Dean


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