Replacing Potterton EP2000 with Hive

3 Jan 2021
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United Kingdom

I hope someone can help me please. I've installed Hive previously on a Vaillant Combi which was straightforward simply requiring connections at the boiler as there was no previous separate thermostat. I've just purchased my first home and I'm looking to install Hive again on a relatively new system with a conventional boiler system featuring a Worcester Greenstar 12Ri, Potterton EP2000 with a separate thermostat on from what I can understand to be a Y plan system as there's a hot water tank and mid position valve.

I've included the photos below to show the set up and wiring centre.




As far as I can interpret the wiring scheme remains the same however I do appreciate I'd also have to isolate existing themostat by either disconnecting the wiring at the wiring centre, make safe by isolating the wiring once the existing thermostat is removed or leave it set to max. I also understand that the link wire from L to 5 needs to be removed and the remaining brown wire can in 5 can then be connected to L. Am I also right in my thinking that for the all other connections I could use Wago connectors to remake all other connections not available on the Hive backplate and leave these in the wall cavity.

EP2000 to Hive
N to N
L to L
1 to 1 (HWOFF)
2 to 2 (CHOFF)
3 to 3 (HWON)
4 to 4 (CHON)
5 to L

If someone can confirm I'm heading in the right direction it would be appreciated.

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Yes, you are about there (y)

The EP connections from your photo are


and the Hive connections are


As you can see they are identical in function, except that the EP has a terminal (5) that has a wire linking it to the (L) terminal. The Hive already has this connection made for you internally, so you simply loose the link wire between the EP (L) and (5), then the remaining wires transfer from the EP to a Dual Channel Hive like for like. [N, L, 1, 3 & 4]

The brown wire in terminal (5) will need reconnecting to (L) as you have figured.

The other terminals A to D are just there as handy terminals, they have no function other than to facilitate the connection of the wires that are in them. The same is true of the earth and neutral connector bars on the right and left. These wires should remain connected together as they are now. You will need new terminals for them.

If there isn't one in place already (I can't be sure from your photo) would sink a single back box into the wall to contain all of the extra terminations and just bring the N, L, 1, 3 & 4 connections into the Hive receiver. [If it's a metal box don't forget to make sure it has an earth connection to it] Make sure you identify the wires before you disconnect them, get them mixed up and it would be almost impossible to fault find over a forum.

You don't show a photo of the existing room thermostat, however as you have figured, it should be decommissioned by removing it and linking the switching wires together to complete the circuit. This is done by bridging the two live switching wires after removing them from the terminals. To do this properly, you will have to trace the thermostat cable back to its origin and find out where it is connected into the circuit. If you need help with this post back details of the room thermostat. Or alternatively set the original thermostat it to its maximum setting and leave it in place, so that it doesn't override the Hive.
Hello stem, thank you for your very comprehensive reply. I had a feeling I was on the right track although as this isn't a regular occurrence your advice provided that little bit of confidence I needed to crack on and get it done. Your suggestion re the back box is sound as I was planning to leave the connections, I remade with Wago connectors loose in the cavity although your solution would ensure the cables remain in one location in case future of a need for future access. For reference the stat is a British Gas RS2 although from I understand you are explaining I shouldn't simply just join the live and switched live with a Wago connector and leave it in the wall cavity behind the old stat; the right way being to remove the cable and bridge at the origin? Thanks again!
I seem to remember the BG RS2 is actually a rebadged Drayton RTS1. If so, there are 4 terminals. Marked L 3 2 N. You can leave the thermostat in place and insert a link between terminals L and 3 that will by-pass the thermostat and complete the circuit. Wiring regulations mean that you shouldn't leave a a live cable in a wall with no external accessory visible to indicate its presence. If your thermostat has different terminals, post back their details.

However, if you wish to remove the thermostat from the wall, then trace the cable from the thermostat back to its origin and note where the wires from terminals L and 3 are connected, then remove the thermostat cable completely. then insert a link between the terminals where the wires going to L and 3 have just been removed from so that they are electrically joined together.

Any wiring terminals should be contained inside an enclosure. It's bad practice to leave them exposed even if in a cavity.
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Just an update to let you know that it's worked a treat, so thank you very much for your guidance which was very much welcomed; just the stat to contend with next. The only significant issue I have is sinking a box into the wall, the kitchen was fitted by a very large UK DIY chain and the quality of the workmanship is sub standard throughout so from your explanation of how it should be I'm left to contend with what you can see in the attachment, a small aperture cut into a tile to permit cable access. Perhaps it's appropriate for me to submit an enquiry on another subforum so please let me know if that's the case however perhaps can you offer any advice as to how a tile can be cut in situ so I can fit the box or if there is another acceptable solution. This tiled area in the corner of the kitchen extends half a meter square in to the kitchen and also has the waste water connections behind it. Thanks.


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Hmmm......Yes I see what you mean. Normally I just draw around the outside of the back box and carefully drill a series of holes with a small new sharp drill bit, however it will be a delicate operation to do that if there isn't physically any wall behind the area you are drilling to support the tile whilst drilling.

If there is a big void behind the tile and you can enclose the wires in small junction boxes so that just the sheath is exposed and then push them into the void that might be one way around it....


....or as you suggest, post on the tiling forum see if anyone has any ideas about cutting the tile.

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