Hello people
I am taking on replacing my Brother in-laws LP241 with a gen 3 Nest and have a couple of questions I hope someone can assist with.
I am comfortable with the wiring I need to do replacing the drayton programmer with the nest unit, but just for confirmation;
N - N
L - L
Drayton 1 - Nest 4
Drayton 2 - Nest 1
Drayton 3 - Nest 6
Drayton 4 - Nest 3
bridging Nest L - 2 & 2- 5
The area I have questions about is the thermostat. I need to remove the existing and replace with the nest as the kit does not have the table stand or the power cable, so I need to feed it from the cables in the wall.
The wires from the thermostat go upstairs to the junction box, which is located in the same cupboard as the hot water tank and I will not have a wire long enough to bell out the cable end to end. As you can see from the picture, the original installer has gone off reservation, I have a strong suspicion that the thermostat wires, red, yellow and blue are coming in second from left and terminating in 8 & 13. I plan to check the switched live (yellow?) by having the heating on, thermostat turned down/off which should show zero volts and then turning on the thermostat which should then liven up terminal 8. For the red wire in terminal 13, I was going to check live with the drayton unit on which would show live and then turn off the drayton unit and this terminal should go dead, will this work to properly identify the cables??
Once properly identified and considering I need a power supply to the nest thermostat, I was going to remove and cap off the yellow wire, leave the blue neutral in place, move the white cable in 8 - 13. The issue I have is I am not sure where the red wire goes as I need this for a permanent live to the nest thermostat, can it stay where it is as it will be live whenever the nest wall unit is live??
Any help would be greatly appreciated, thanks in advance