Danfoss RT52 Installation Instructions User Instructions page 6

Thermostat Wiring (not RF models)
GB
RX Receiver Wiring (RF models only)
RX1
RX2 & RX3
NB. For mains voltage operated systems link terminal 2 to mains live supply.
6
ELECTRONICS
N L 1 2 3 4
ELECTRONICS
A B C 1 2 3 4 5 6
N L
L
N
COM ZONE ZONE
1 OFF
1 ON
COM
ZONE ZONE ZONE
1 ON 1 OFF 2 ON
TERMINAL 6
RX3 ONLY
ZONE
3 ON