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Hi,
I've just purchased a 3rd gen Nest as they are reduced for Black Friday.
I was hoping to get a sanity check on my wiring plans. I understand that I have a Y Plan system.
Existing Timer (Honeywell C21):
N = 230v Neutral
L = 230V Live
Earth
1 = HW OFF
2 = CH OFF (NOT USED)
3 = HW ON
4 = CH ON
Nest Heat Link:
N = 230v Neutral
L = 230v Live
1 = CH Satisfied (OPTIONAL)
2 = CH Common
3 = CH Demand
4 = HW Satisfied (OPTIONAL)
5 = HW Common
6 = HW Demand
OT1 = OpenTherm (NOT USED)
OT2 = OpenTherm (NOT USED)
EARTH
T1 = 12V DC (to Nest)
T2 = 12V DC (to Nest)
So therefore I'm planning to wire as follows:
(Honeywell C21 - Nest Heat Link)
N - N
L - L
Earth - Earth
1 (HW OFF) - 4 (HW Satisfied)
3 (HW ON) - 6 (HW Demand)
4 (CH ON) - 3 (CH Demand)
Link commons to 230V Live by:
Linking Heat Link Live to Terminal 2
Linking Heat Link Terminal 2 to Terminal 5
Send 12V to Nest by:
T1 = Old thermostat wire
T2 = Old thermostat wire
Does this look correct?
If so I just need to find and identify where the wires are to the old thermostat. I understand it would have been wired in series with the programmer, so hopefully the wires will be behind the backplate!
I had read that when replacing the old thermostat the wires would need to be connected for the heating to function, but if they are being removed from the series wiring and used instead to power the Nest, then I guess this should work fine?
Any help much appreciated.
I can always post a pic of the current wiring but hopefully I've explained it clearly.
Cheers,
Phil
I've just purchased a 3rd gen Nest as they are reduced for Black Friday.
I was hoping to get a sanity check on my wiring plans. I understand that I have a Y Plan system.
Existing Timer (Honeywell C21):
N = 230v Neutral
L = 230V Live
Earth
1 = HW OFF
2 = CH OFF (NOT USED)
3 = HW ON
4 = CH ON
Nest Heat Link:
N = 230v Neutral
L = 230v Live
1 = CH Satisfied (OPTIONAL)
2 = CH Common
3 = CH Demand
4 = HW Satisfied (OPTIONAL)
5 = HW Common
6 = HW Demand
OT1 = OpenTherm (NOT USED)
OT2 = OpenTherm (NOT USED)
EARTH
T1 = 12V DC (to Nest)
T2 = 12V DC (to Nest)
So therefore I'm planning to wire as follows:
(Honeywell C21 - Nest Heat Link)
N - N
L - L
Earth - Earth
1 (HW OFF) - 4 (HW Satisfied)
3 (HW ON) - 6 (HW Demand)
4 (CH ON) - 3 (CH Demand)
Link commons to 230V Live by:
Linking Heat Link Live to Terminal 2
Linking Heat Link Terminal 2 to Terminal 5
Send 12V to Nest by:
T1 = Old thermostat wire
T2 = Old thermostat wire
Does this look correct?
If so I just need to find and identify where the wires are to the old thermostat. I understand it would have been wired in series with the programmer, so hopefully the wires will be behind the backplate!
I had read that when replacing the old thermostat the wires would need to be connected for the heating to function, but if they are being removed from the series wiring and used instead to power the Nest, then I guess this should work fine?
Any help much appreciated.
I can always post a pic of the current wiring but hopefully I've explained it clearly.
Cheers,
Phil
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