Navien NFC-250/175H, Руководство по установке, Страница: 43 / 151

43 Installing the System Piping
3.6.10 External Recirculation with Dedicated Return Line (Always On, Weekly,
Intelligent)
External Recirculation Mode
For best performance, select the intelligent or weekly option in the external recirculation DHW recirculation menu.
Note
Combi pre-heat is the default mode for DHW recirculation. To select external recirculation, refer to the
combi pre-heat and external recirculation sections in "11.5.3 Setting the DHW Operation" on page
114 for details.
N
A/H
DHW
PRI
L
N
L
N
L
N
L
N
L
Z3
Z2
Z1
N
A/H
DHW
PR
I
L
N
L
N
L
N
L
N
L
Z3
Z2
Z1
SUPPLY
TEMPERATURE SENSOR
RETURN OUTDOOR T/S_ZONE3
R W C
T/S_ZONE2
R W C
T/S_ZONE1
R W C
AC24VN
AC24VL
lLWCO
R
W
C
T/S_Re
cir
COM
NO
NC
ZONE_V
/V
3
COM
NO
NC
ZONE
_V
/V
2
COM
NO
NC
ZONE
_V
/V
1
* Recirculation Pump
Pump Ground
DHW Supply
Return Water
City
Water
Supply
Check
Valve
Check
Valve
Recirculation
Pump
(max. 2.5A)
* A Taco 008-BC6 or Grundfos 15-42 BUC7 (or equivalent) circulation pump is recommended for use with the NFC-H boiler and
DHW recirculation systems.
* When using the external recirculation mode, observe the following maximum recirculation pipe lengths including fittings ( 3 /
4
”
pipe is recommended). Lengths in excess of these limits will require a larger recirculation pump.
Maximum Equivalent Copper Pipe Lengths
Pipe Diameter
1
/
2
"
3
/
4
"
Maximum Pipe Length 100 ft (30 m) 400 ft (120 m)
Note
If a dedicated return line is installed for external recirculation, the Always On, Weekly, and Intelligent
modes can be used after installing a recirculation pump.