Navien NFC-175, Installation & Operation Manual

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41 Installing the System Piping
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
N
A/H
DHW
PRI
L
N
L
N
L
N
L
N
L
Z3
Z2
Z1
AC24VN
AC24VL
lLWCO
R
W
C
T/S_DWH
R
W
C
R
W
C
T/S_CH_ZONE1
T/S_ZONE2
SUPPLY
TEMPERATURE SENSOR
RETURN OUTDOOR T/S_ZONE3
R W C
N
A/H
DHW
PRI
L
N
L
N
L
N
L
N
L
Z3
Z2
Z1
Zone pump 1
(max. 2.5 A)
Zone pump 2
(max. 2.5 A)
Zone pump 3
(max. 2.5 A)
Recirculation pump
(max. 2.5 A)
Pump Ground
NC
NC
COM
NC
NC
COM
LWCO
AC24VL
AC24VN
NC
NC
COM
ZONE1
ZONE2
ZONE3
AC24VN
AC24VL
lLWCO
R
W
C
T/S_Recir.P
R
W
C
R
W
C
T/S_ZONE1
T/S_ZONE2
SUPPLY
TEMPERATURE SENSOR
RETURN OUTDOOR T/S_ZONE3
R
W
C
Thermostat 1
Thermostat 2
Thermostat 3
Recirculation
Timer, Aquastat,
or HotButton
*
* If the DHW recirculation menu is set to the Always On, Intelligent, or Weekly option, no aquastat or additional HotButton is required.
Note
●
The C terminals are for optional connections with 24 V thermostat COMMON.
●
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.