Combi Wiring.

[Spudnik]

Chaps..

Got a Gloworm 38CDXi combi to wire up.

Now, the system is being zoned with 2 x 2port valves with 2 x room stats upstairs and downstairs.

What i ned to know is, is it 3c& earth to each stat with LN & switch live or just L & SL 24V ?

Looking at page 36 of the following, it shows a 24V room stat across the link which needs to be removed, but the other diagram shows 230V system controls with a volt free contacts stat i assume???

Any quick help much appreciated!!

http://www.glow-worm.co.uk/products/pdf/current/Ultracom_cxi_installation_manual.pdf

 

[nrbspark]

Hi Jason

The way I read it is you would have to disable the internal clock if you are to use an external one, remove the link across the 24 v terminals and then introduce a 240 v switched live from your external controls (Stats and/or clock) onto terminal R of the boiler connection block to fire the boiler for heating.

Hope this helps

 

[Spudnik]

Thanks for that.

Although, there wont be an external time clock, unless i need to install one?

 

[nrbspark]

I am not 100% sure but I think there is now a requirement for being able to have timed and temperature controls on heating systems.

But this may be the plumbers responsibility

We just have to connect and fuse correctly.......

 

[Spudnik]

Sorry, meant to say that it does have a built in time clock, so i shouldnt need an external one?

 

[nrbspark]

Internal or external is fine as long as it has one or the other.............

 

[ajelec10]

Hi, Just had a look at this post,
Your right the control system has to have both a time clock and room thermostat, this is to provide boiler interlock for energy effieicy, its also worth noting that all radiators have to have a TRV (thermoststic radiator valve) fitted, appart from the one in the same room as the room stat.

I have found lots of plumbers thinking that all TRV's and a time clock is sufficent!!

Looking at the diagram Jason, it i think there are two ways to wire the boiler, you can either use the 230v switch live in on the R terminal or use the 24v volt free side.
If its an internal time clock then i would use 230v stats with 3c+e these control the motors in the zone valve then the volt free contacts in the zone value (orange + grey) wires can then be used to either switch a 230v feed to the R terminal or make the 24v volt free connections.

If you have to fit an external time clock i would recomend programable room stats then you have independat time and temp control on both zones. But this can some times be a little complex for some clients to work, as i found out when i did it in my parents??? lol.

Hope this helps.

AJ