Replacing BG Programmer & Wireless Stat with Nest 3rd Gen

26 Nov 2017
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United Kingdom

I wondered if someone would be able to confirm my approach or advise alternatively.

I have a Y-Plan system comprising:

British Gas 330+ Boiler
BG UP2 Controller
BG WR1 Wireless Receiver & Stat

I want to fit a 3rd Generation Nest and am pretty confident with the connections, but want to check a small element. In contrast to a lot of the systems I've seen in other guides, my wireless receiver is wired directly from the back plate of the controller, as below:


The cable on the left is the one running to the receiver, with the other off to the junction box.

The wiring in the receiver looks like this:

Wireless Reciever.jpg

As I'll be removing the receiver and controller, my logic is that the remaining wiring should be connected as such:

  • Blue - Neutral - Nest N
  • Brown - Live - Nest L, with link to 2 & 5
  • Black - (Currently coupled with receiver Black in Earth connector!) - Central Heating N/O - Nest 3
  • Green/Yellow - (Currently in 2) - Hot Water N/C - Nest 4
  • White - (Currently in 3) Hot Water N/O - Nest 6

I'm hoping that I've got this correct (it's mainly the coupled Black wires that I need to check) and that I will, therefore, not need to touch the junction box.

You help, in advance, is much appreciated
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Hi Kev

First of all I guess that there is a problem with the wireless receiver because the brown link, shouldn't be there, it has been added to bypass the receiver. But don't worry about it.

You have figured it out OK, so I can confirm as follows:

Disconnect all of the 4 wires in the cable from the programmer to the receiver and remove the cable.

With the remaining cable

The N and L are straightforward, move them to the Heatlink N & L as applicable
The green and yellow wire in terminal 1 is 'HW Satisfied' (Nest 4)
The remaining black wire under the earth tether is 'CH call for heat' (Nest 3)
The white wire presently in terminal 3 is 'HW call for heat' (Nest 6)
Link the (Nest L, 2 & 5)

The existing installation is not good in that the green and yellow earth wire has been use as a live conductor. This is not good practice, and at least should have a brown sleeve on to identify it as a live.
Thanks Stem

I share your view on the original install. Done by British Gas, who sent a couple of jokers around.

Can’t thank you enough for confirming the connections. The link in the receiver has always concerned me.


Wow! for a supposedly professional install it's diabolical really. :eek:

No clamps or fixings securing the cables, too much exposed copper in the terminations, using an earth tether as a live connection, and an earth wire as a live conductor. Finally even though the original programmer didn't need an earth connection, one should still have been provided just in case for future use.

To include so many errors when connecting just two cables is pretty impressive. But the creme de la creme...

The link in the receiver has always concerned me.
No point in the receiver being there. Once the timer switched on, the heating would have been permanently 'on' regardless of what the thermostat was telling it to do.
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