Replacing Horstmann Channel XL thermostat with Nest

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Hi

I am attempting to replace a Horstmann Channel XL plus with a Nest thermostat.
I have not been able to find a wiring diagram for this particular Horstmann model. I can find the diagram for the series 2 but that appears to be different.
I was expecting to see a wires as below:
Earth (empty)
Neutral
Live
1 - heating on signal
2 - live
3 - heating off signal
4 - hot water on
5 - live
6 - hot water off (this position is empty)

There is a remote thermostat controller wired in as well but I was ignoring this and planning on just removing it.

Can I assume that as position 6 is empty my system doesn’t need a hot water off signal?

I have attached a photo of the current set up.


http://horstmann.securemeters.com/files/2514/6916/4123/installer_guide_H37XL-ISeries21.pdf
 

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Hi

I am attempting to replace a Horstmann Channel XL plus with a Nest thermostat.
I have not been able to find a wiring diagram for this particular Horstmann model. I can find the diagram for the series 2 but that appears to be different.
I was expecting to see a wires as below:
Earth (empty)
Neutral
Live
1 - heating on signal
2 - live
3 - heating off signal
4 - hot water on
5 - live
6 - hot water off (this position is empty)

Are you sure the CH and HW aren't the wrong way round there? This manual for the Series 2 suggests it is, and that 123 are for HW and 456 for CH.

Can I assume that as position 6 is empty my system doesn’t need a hot water off signal?

Not if the diagram I've linked to matches your setup.

I have attached a photo of the current set up.

Always a worry to see the CPC used as a switched live, but at least they marked it (not that that makes it acceptable, but it could be worse!). ;)
 
Last edited:
Thanks. That makes more sense now.
So the way I see it the yellow and wire joined in the terminal block (to a black wire) should go to position 6 but is taken off to a feed from the remote thermostat.
 
your origional set up is not wired correctly , there should be a link between L&2&5 you have a link between L&2 but a different wire in 5 that is wrong
 
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your origional set up is not wired correctly , there should be a link between L&2&5 you have a link between L&2 but a different wire in 5 that is wrong
The wire into 5 comes via the remote thermostat. Not how I would have wired it but it works.
 
Can I assume that as position 6 is empty my system doesn’t need a hot water off signal?
Position 6 is CH off, you dont need a wire in there, you do need a wire in HW off existing terminal 1, you have a Y plan system, plenty of wiring diagrams online
 
The wire into 5 comes via the remote thermostat. Not how I would have wired it but it works.

Yes, it would indeed work - the electrons don't really care whether the timer or thermostat comes first in a series circuit! :)
 

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