Navien NFB-175H, Installation Manual, Page: 40 / 135

40 Installing the System Piping
With 24VAC connections
COM
A/H
DHW
PRI
NO
NC
N
L
N
L
N
L
COM
A/
H
DHW
PRI
NO
NC
N
L
N
L
N
L
COM
NO
NC
ZONE1
COM
NO
NC
ZONE2
COM
NO
NC
ZONE3
AC24VN
SUPPLY RETURN OUTDOOR DHW TANK
AC24VL
LWCO
R
W
C
R
W
C
R
W
C
R
W
C
DHW pump
(max. 2.5 A)
Zone pump 2
(max. 2.5 A)
Zone pump 3
(max. 2.5 A)
Boiler pump
(max. 2.5 A)
LWCO
AC24VL
AC24VN
NC
COM
ZONE3
COM
NC
NC
ZONE3
AC24VN
SUPPLY RETURN OUTDOOR DHW TANK
AC24VL
LWCO
R
W
C
R
W
C
R
W
C
R
W
C
Thermostat 1
24 VAC N
Thermostat Input
24 VAC L
DHW Aquastat
(priority)
Thermostat 2
24 VAC N
Thermostat Input
24 VAC L
Thermostat 3
24 VAC N
Thermostat Input
24 VAC L
Pump Ground
Note
If the DHW Tank is connected to the priority terminal, the T/S Zone 1 input is not available.