Re: Fw: Replacing and automating the Central Heating switch

[Neil Fuller <neil.fuller@xxxxxxxxx>]

Gareth

Palmlodge times out so I can't comment on the pretty picture ;-)

If you want separate control of the HWS and CH, you will need to use two
CBUS relays.

One will connect the live supply (fused at 3 amps) to the live supply on
the HWS thermostat on the cylinder.

The other will connect the live supply to the live supply on the CH
thermostat.

When the HWS CBUS relay is energised, a live supply is applied to the
HWS thermostat. If the HWS cylinder temp is low, the thermostat makes
and energises the HWS actuator. When the valve opens, allowing primary
hot water from the boiler to flow around the primary coil in the
cylinder, an end switch on the actuator makes and supplies a live signal
to the boiler and pump.

Once the HWS is satisfied, the thermostat opens which removes the signal
to the actuator which then closes via a spring (it motors open, springs
shut). As the actuator closes the valve, the end switch opens and the
boiler and pump stops.

A similar situation applies to the CH except the thermostat is on the
wall and the valves allows the hot water to flow around the radiators.

Other systems exist such as the Honeywell Y plan which uses one 3 port
valve. However, the basic principle is the same with the thermostats
supplying a signal to the valve which opens the heating port, the HWS
port or both.

Systems can have other additions such as frost stats or
"intelligent"
room stats that provide OSS and fabric protection.

If you are still struggling, tell me which system you have (2 x 2 port
valves or 1 x 3 port valve) and I'll do you a drawing.

HTH

Regards

Neil

Gareth Cook wrote:

>Here's a pretty picture of the back of the timer switch = which tells
you
>what the connections are:
>
>http://tinyurl.com/b93pb
>
>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 01/02/2006 13:54 -----
>
>Discussion
>Main Topic
>
>ukha_d@xxxxxxx
>Today 13:45
>
>.
>Subject:
>.
>[ukha_d] Replacing and automating the Central Heating switch
>.
>Category:
>
>
>
>Just wanted to clarify something here - I was thinking of CBUS'sing the
>Heating system by just bypassing the timer switch.
>
>Currently we have a seperate temperature sensor - I wont touch that.
What
>Im thinking I can replace is the timer switch - All it seems to do is
just
>
>make a electrical connection at a certain time for the heating and the
>water tank (one for each)
>
>So in theory, I should be able to take the live and common for these ,
and
>
>just plug them straight into a CBUS relay channel (just like an X10
AM10).
>
>I can then use Comfort's logic to activate the relays etc, and have a
CBUS
>
>switch show the status and can use that to override as well.
>
>I'll also assume that it's 240v, and that it's less than 10Amps !
>
>All make sense ? Anything Im missing ?
>
>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
>
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