Navien NFC-175 Installation & Operation Manual page 35

3.6.7 System Application - External Recirculation with HotButton and NaviCirc
External Recirculation Mode
For best performance, select the manual option in the External recirculation DHW recirculation mode.
Combi pre-heat is the default mode for DHW recirculation. To select external recirculation, refer to the combi pre-heat and external
Note
recirculation sections in "11.3.4 Setting the DHW Operation" on page 90 for details.
* Recirculation Pump
Check
Valve
City Water Supply
* A Taco 008-BC6 or Grundfos 15-42 BUC7 (or equivalent) circulation pump is recommended for use with the NFC boiler and DHW recirculation systems.
* When using the external recirculation mode, observe the following maximum recirculation pipe lengths including fittings (
in excess of these limits will require a larger recirculation pump.
Maximum Equivalent Copper Pipe Lengths
Pipe Diameter
Maximum Pipe Length
To use HotButton mode, install a HotButton and recirculation pump.
Note
●
Install the NaviCirc recirculation valve to the faucet furthest from the NFC boiler.
●
If installed in close proximity to the boiler, faucets further down the supply line will take longer to receive hot water.
●
Recirculation
Pump
(max. 2.5A)
Recirculation pump
(max. 2.5 A)
SUPPLY RETURN
TEMPERATURE SENSOR
Return Water
/ "
1 3
2
100 ft (30 m) 400 ft (120 m)
lLWCO
AC24VL
AC24VN
SUPPLY RETURN OUTDOOR T/S_ZONE3
TEMPERATURE SENSOR R W C
OUTDOOR T/S_ZONE3
R C
W
Pump Ground
NaviCirc
(Sold Separately)
DHW Supply
/ "
4
lLWCO
AC24VL
AC24VN
3
/ " pipe is recommended). Lengths
4
Wired
HotButton
Wired
HotButton
Wired
HotButton
About the Boiler 35