Secure Channelplus H27XL to Drayton Wiser Hub (WT734R)

[firebot]

Hi,
I've got Secure ChannePlus H27XL which I want to swap with Drayton Wiser Hub (WT734R - three channel) Could anyone please help me with the wiring of these below? (N & L I can see how to wire clearly)

Here is a diagram for Secure ChannelPlus H27XL:

And here is a diagram for Drayton Wiser Hub (WT734R):

Maybe I ordered the wrong one, but that's what was advised based on having 2 zones/2 thermostats in the house (I've got one downstairs and one on the top floor).

As well as that, I am not sure how it's important but there is an OpenTherm I can optionally connect and it's apparently supported by my Baxi Assure 36 Combi Boiler I've got. But as of yet I don't know if there are cables coming to the wallplate to H27XL (as I haven't started the job yet). Do I need to bother with that? I can also take some pictures of the wallplate if that would help.

 

[Deleted member 267285]

Is the Centaur still connected, or is it being used for the heating? Odd setup with a combi if not. Do you have hot water cylinder? If Combi only, then x2 kit 1 would be better. Not sure you’d get opentherm to work with x2 zones?

 

[oldbutnotdead]

As above, Opentherm doesn't cooperate very well with multizone systems.
If you set your shiny new Drayton roomstat as channel 3 (the 2nd heating zone) Opentherm does not call for heat from the boiler.
Drayton do not support Opentherm on the 3 channel Hub- it does seem to control my boiler (Intergas Rapid32) but does some odd things (eg when Hot Water is OFF on the Wiser hub, the max temperature of the combi dhw is locked at 40° c, you can alter it in the user menu but it doesn't save. If Hot Water is ON you can set and save a more useful temperature...but you lose that setting if HW goes OFF.
Yes I have a non-standard setup, cylinder and combi.
Another trap for you- your existing controller uses volt-free relays. That Wiser hub is 240v (or Opentherm) only. Many many boilers are controlled by 240v signalling but not all- worth checking before you get too excited

 

[firebot]

Is the Centaur still connected, or is it being used for the heating? Odd setup with a combi if not. Do you have hot water cylinder? If Combi only, then x2 kit 1 would be better. Not sure you’d get opentherm to work with x2 zones?

I am sorry, but I am not sure what you mean by Centaur. Could you clarify for me what it means? Yes, I've only got a combi. No water cylinder. Well, kit 3 was advised by wiser as I followed their product selection guide based on my selection for combi boiler and 2 thermostats. You can check it here: https://wiser.draytoncontrols.co.uk/product-selector

 

[firebot]

As above, Opentherm doesn't cooperate very well with multizone systems.
If you set your shiny new Drayton roomstat as channel 3 (the 2nd heating zone) Opentherm does not call for heat from the boiler.
Drayton do not support Opentherm on the 3 channel Hub- it does seem to control my boiler (Intergas Rapid32) but does some odd things (eg when Hot Water is OFF on the Wiser hub, the max temperature of the combi dhw is locked at 40° c, you can alter it in the user menu but it doesn't save. If Hot Water is ON you can set and save a more useful temperature...but you lose that setting if HW goes OFF.
Yes I have a non-standard setup, cylinder and combi.
Another trap for you- your existing controller uses volt-free relays. That Wiser hub is 240v (or Opentherm) only. Many many boilers are controlled by 240v signalling but not all- worth checking before you get too excited

Well, one of the problems that I do not understand is how is it wired to know I've got 2 zones.. From the diagram above in the Secure controller (H27XL), it only has CW ON/CH OFF. I assume that's on and off for heating. Do thermostats directly connected to the boiler control which zone to heat?
The second thing I do not understand why I've got 2 CH connections on Drayton Hub... I think one will be redundant then?
I still got a feeling it needs to be connected via Opentherm so I can use 2 thermostats as there is no other link.
Also, you've mentioned trap - that existing controller is using volt-free relays. Isn't L connected to 2 relay which switches? I mean it's still 240v anyway. No?

The further I read and do my investigation the further I understand maybe I need an electrician to sort it out for me, but I am not giving up yet. But it would be great to get someone here to help me out with the wiring...

 

[ericmark]

Tangled web, in theroy only the single channel will work with OpenTherm, but it seems people have used them, there is a thermostat EPH I think do a thermostat which can be configured as master/slave with OpenTherm, but does not connect to TRV heads, where the Wiser does.

There is really no point having electronic TRV heads and hard wired motorised valves as they do the same job.

The building regulations were read by the trade as requiring hard wired motorised valves, but a number of LABC's have stated they consider TRV's alone to comply. I am no lawyer.

The question is should the two valves be wired together, and to be Frank I don't know.

As an electrician I can make it work, but as to working efficiently I don't know, a heating and ventilation engineer may know better how to arrange it, but much will depend on house design.

I made a mess of my own heating, it is not easy.

 

[oldbutnotdead]

If your hot water is coming from the combi (no hot water cylinder) then good odds the HW side of your existing controller is actually running one of the heating zones.
You don't need an electrician but you do need some basic electrical knowledge and test equipment so that you KNOW what things do rather than assuming (which can cause expensive and dangerous problems).

 

[Taylortwocities]

And, or course, the middle of winter is the very BEST time to mess around with your heating system!

 

[Deleted member 267285]

I am sorry, but I am not sure what you mean by Centaur. Could you clarify for me what it means? Yes, I've only got a combi. No water cylinder. Well, kit 3 was advised by wiser as I followed their product selection guide based on my selection for combi boiler and 2 thermostats. You can check it here: https://wiser.draytoncontrols.co.uk/product-selector

Apologies, the Centaur was the predecessor. Also you may be able to use the Kit 3, so again apologies, was having an off day yesterday.