Navien NFB-175H Installation Manual page 37

3.6.3 Wiring Diagram - Zone Pump System
The NFB-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
Boiler pump
(max. 2.5 A)
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.
●
SUPPLY RETURN OUTDOOR
Pump Ground
NC
NC
COM
NC
LWCO
COM
AC24VL
LWCO
AC24VN
AC24VL
AC24VN
NC
NO
COM
NC
NO
COM
NC
NO
COM
LWCO
AC24VL
AC24VN
C
W
R
C
W
R
C
W
R
C
W
SUPPLY RETURN OUTDOOR DHW TANK
R
DHW TANK
C
W
R
C
W
R
Thermostat 1
C
W
R
Thermostat 2
C
W
R
Thermostat 3
Installing the System Piping 37