Navien NFC-175 Installation & Operation Manual page 41

3.7.4 Wiring Diagram - Zone Pump System with DHW Recirculation
NFC boilers can use both the 3 zone heating system and the DHW recirculation feature. The following wiring diagram shows the 3 zone system
and the DHW external recirculation feature.
Without 24VAC Connections
Recirculation 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 the DHW recirculation menu is set to the Always On, Intelligent, or Weekly option, no aquastat or additional HotButton is required.
The C terminals are for optional connections with 24 V thermostat COMMON.
Note
●
When using combi pre-heat, using a recirculation pump is not necessary. Select combi pre-heat on the DHW recirculation menu
●
of the parameter setting part.
When using external recirculation, install a recirculation pump and select external recirculation in the DHW recirculation menu.
●
lLWCO
AC24VL
AC24VN
SUPPLY RETURN OUTDOOR T/S_ZONE3
TEMPERATURE SENSOR R W C
Pump Ground
SUPPLY RETURN OUTDOOR T/S_ZONE3
TEMPERATURE SENSOR R C
W
Thermostat 3
NC
NC
COM
NC
NC
COM
NC
NC
COM
LWCO
AC24VL
AC24VN
lLWCO
AC24VL
AC24VN
*
Recirculation
Timer, Aquastat,
or HotButton
Thermostat 1
Thermostat 2
Installing the System Piping 41