Navien NFC-250/175H Installation Manual page 46

3.7.3 Wiring Diagram - Zone Pump System
NFC-H boilers can operate a heating system with up to 3 zones. The following is the wiring diagram for a zone
pump system with 3 zones.
Without 24VAC Connections
Zone pump 1
(max. 2.5 A)
Zone pump 2
(max. 2.5 A)
Zone pump 3
(max. 2.5 A)
If you have a 24 V thermostat, connect it to the R & C terminals on the boiler's PCB.
Note
●
The C terminals are for optional connections with 24 V thermostat COMMON.
●
46 Installing the System Piping
lLWCO
AC24VL
AC24VN
SUPPLY RETURN OUTDOOR T/S_ZONE3 T/S_ZONE2 T/S_ZONE1
TEMPERATURE SENSOR R C R C R C
W W W
Pump Ground
SUPPLY RETURN OUTDOOR T/S_ZONE3 T/S_ZONE2
R C R
TEMPERATURE SENSOR W
Thermostat 3
Thermostat 2
T/S_ZONE1
C R C
W W
Thermostat 1