Replacing Potterton EP2 and Centaurstat 7 with Drayton Wiser

[Tommohawk]

Hi and Happy New Year to all.

Currently I have perfectly functioning Y plan + Greenstar Ri system boiler, controls as in thread title. I'm guessing it had a simple stat at some point which was replaced with the Centaurstat. I want to switch the EP2 to a Drayton Wiser so I can control both CH and DHW remotely.

I think the EP2 backplate differs from the Drayton so looks like it'll need changing, and there a few things with the swap that I cant quite figure out.

Pics attached show current EP2 wiring, EP2 wiring diagram and Drayton diagram.

Looks like I'll need to put wires from pins B and C and D into block or Wago cos it seems theres no spare terminals on the Drayton back plate.
Pins N and L, plus pins 1, 3 and 4 should just go to same pins on Drayton plate.
Can someone confirm the above is correct please?

Not sure re pin 5 - looking at EP2 diagram this should just be a link from L, but it doesnt come from there - it's connected to one of the other cables. Without the link, it seem CH wouldnt get power. So maybe the wire on 5 is picking up permanent L from somewhere else?

I guess I'll also have to connect the wires at the existing stat so its permanently connected. Alternatively I could link them at the backplate - - but not confident re that if the wiring is non standard?

One other thing to throw in the mix. I said the system works perfectly -it actually has one minor glitch. The diverter valve buzzes sometimes, which I read can be because it's continues to get power under some circumstances. If I switch the HW on briefly, then off again it stops. I think this is a total red herring but just mention it in case it's relevant.

I'd be so grateful for any thoughts - thanks!

 

[CBW]

Sounds logical. Have you bought the Wiser yet?

 

[Tommohawk]

Hiya... no not bought yet. Just want to be sure the plan is good before parting with any dosh.
What's your thoughts on the pin 5 connection?

 

[CBW]

I think it could be getting a feed from elsewhere, however, the Wiser switches internally.

 

[Tommohawk]

OK - so you think just park that wire somewhere?

 

[CBW]

Yeah, possibly in a Wago in case it’s needed.

 

[Tommohawk]

OK great thanks for that, very helpful. I seem to have few things on the go at the moment but once I've sorted parts and done install I'll post back to confirm all good.... hopefully!

 

[ianmcd]

Well as you have found out, the EP range were sold as a wiring centre and programmer built in to one, if you want to replace with a modern unit tou will have to create a new wiring centre to accomodate the connections you wont be able to do it otherwise

 

[stem]

It might help you to see what's involved if you look at some of the EP changes that have been done previously. There's an example here. In this instance it's being replaced with a Dual Channel Hive, but the Hive connections are the same as for a Two Channel Wiser.

 

[Tommohawk]

It might help you to see what's involved if you look at some of the EP changes that have been done previously. There's an example here. In this instance it's being replaced with a Dual Channel Hive, but the Hive connections are the same as for a Two Channel Wiser.

Brilliant thanks - I searched (honest) and found a number of related threads but somehow missed that one. I'd pretty much concluded that the EP2 replaces a conventional wiring centre, not least because I couldnt find one anywhere else! My plan is to do as you suggested on that thread ie recess a box behind the backplate housing a connector block for terminals B - E and probably 5 too.

Well as you have found out, the EP range were sold as a wiring centre and programmer built in to one, if you want to replace with a modern unit tou will have to create a new wiring centre to accomodate the connections you wont be able to do it otherwise

Thanks for that - as per above, hopefully I can create a mini wiring centre behind the new backplate, rather than start over with a conventional wiring centre.