Drayton Wiser and existing thermostat

[simon bone]

I am hoping someone can help with my query.

I am replacing my existing Centaurplus c27 controller and Honeywell thermostat with the Drayton wiser 1 channel system to control my vallient combi boiler (no separate hot water).

My first query is in regards to the thermostat. I understand I should taking this out of the equation as wiser links to wireless unit. However I was wondering if I could just leave thermostat in place turned to full on in case I wanted to move in future and swap system back.

If not good practise then I know I need to address open circuit. Is this just a case of connecting the thermostat cable 1 and 3 together?

At the controller the existing unit and the wiser controller share the same back plate. The Drayton wiring diagram (see link: https://wiser.draytoncontrols.co.uk..._24-11-17_t3612_wiser_instructions_issg_g.pdf) matches for N brown (live) and L Grey (sleeved blue / Neutral) so no change.

However the Drayton wiring diagram calls for heating on link to 3. The existing configuration has a separate cable (thermostat link I believe) connected to 4. Can I just move this to position three? Or because of thermostat change above should I be connEating in some alternative way?

FYI - I am fairly diy competent but would rather not mess up heating. I am happy to change a couple of wires around but would not want to mess with cabling at the boiler so if can be easily changed at the switches any help would be appreciated.

Thank you for reviewing and any advice in advance.

 

[flameport]

The C27 is a 2 channel device, not normally used with a combi boiler. If that is really what you have, then 4 is heating on, and the wire there would be connected to 3 on the new Drayton. You also need the link between L and 1 - this is internal to the C27 which is identical in connections to the 2 channel Drayton.

I could just leave thermostat in place turned to full on in case I wanted to move in future and swap system back.

If you must, although surely the point of new items is to get rid of the old ones.
If the existing thermostat is a Honeywell T6360B it won't work properly anyway as there is no neutral connected to it.

connecting the thermostat cable 1 and 3 together?

Yes, that's all the thermostat does when on. It's just a switch. However if you are doing that at the thermostat then the thermostat must be left in place or a blank plate fitted instead, the wires cannot be concealed in the wall as they will still be connected to the supply.

In terms of the wiring, all you need is the L&N supply and the switched output which goes to the boiler connected to 3 on the new Drayton device. Any wiring for the old thermostat is redundant and should be removed.

 

[simon bone]

Flame port

Thank you for detailed reply and feedback. Much appreciated.

Thermostat is definately the c27. It was used on my boiler and hot water tank system hence 2 channels and installer of combi unit retained its use.

You are correct on the thermostat being the non lamped T6360B. You also confirmed my originally reading of wiser diagram needing link between L and 1. I was not sure if this was internal in Drayton unit.

I also take your point on thermostat replacement and will remove and blank as you suggest.

So to confirm my understanding.

1. At controller back plate move current connection from position 4 into position 3
2. Provide a cable link between L and 1
3. At thermostat connect position 1 and 3 via block and also terminate earth in separate block. Cover with face plate.

Hopefully above is correct and thank you again for help.