nest Learning thermostat, Installation Manual, Page: 21 / 144

General specs
Terminal Specification Notes
L 230 V AC/50 Hz mains voltage Live wire
N 230 V AC/50 Hz mains voltage Neutral wire
1 Heating relay normally closed/satisfied 3 A resistive, 1 A inductive
2 Heating relay common 3 A resistive, 1 A inductive
3 Heating relay normally open/call for heat 3 A resistive, 1 A inductive
4 Hot water relay normally closed/satisfied 3 A resistive, 1 A inductive
5 Hot water relay common 3 A resistive, 1 A inductive
6 Hot water relay normally open/call for heat 3 A resistive, 1 A inductive
OT1 OpenTherm wire 1 42 V DC max .
OT2 OpenTherm wire 2 42 V DC max .
If using T1 and T2, connect to earth
T1 12 V DC power output to Nest
T2 12 V DC power output to Nest
Note: T1 and T2 have no polarity at the thermostat .
Maximum cable thickness = 2 mm²
AC power adaptor
Input: 100-240 V AC, 50/60 Hz, 0 .2 A | Output: 5 V DC, 1 .4 A
Heat Link
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