Help with wiring Drayton kit 1

28 Jan 2023
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United Kingdom
Good evening,

I was trying to upgrade the EPH to Drayton wiser kit 1 on a Worcester combi boiler. I have made the connections as indicated in the manual of kit1. However, the CH is not kicking in when called for. The light on the Hub comes on but boiler is not kicking in. Hot water is working perfectly

I have gone through almost all the posts about wiring and all of the post relates to 4 wires.

My previous wall plate only have three wires. I know the wiring I have done is inorrect. Can any wiser help me.

The first pic is my old eph wall plate connection and the second I connected the wires to wiser plate.

Thank you so much


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From the EPH to Wiser..

L -> L
N -> N
3 -> 3
L-2(Com) link -> L-1(Com) link

no connections in 2 or 4 on Wiser.

Your error was attaching the previously sleeved core to the earth terminal rather than terminal 3. You should replace the sleeving on the green/yellow core to indicate it's not an earth but rather a switched live. Note it's bad practice to use a cpc core for anything other than an earth but I don't see another core on your cable.
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Thank you so much. I will give it a go later this evening and report back hopefully with good news.
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Just to confirm the white cable in both pictures is one and the same? In re-checking the pictures the colours look slightly different. You are replacing the EPH by Wiser in an identical location? If not please advise prior to any rewiring.
Sorry, the first pic is the current wiring of the EPH but the second picture I took it from a video grab just to show the connections I made on the Drayton back plate. Yes I will be installing wiser at the same location. Am I good to go ahead with the connections you advised above?
Yes, you are good to continue. Make sure you carefully mark the cpc (yellow/green) core to indicate it's being used as switched live. If you know the location of other end of the cable that should also receive a brown sleeve. You don't want someone in the future thinking it's an earth connection.
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