62
2.4.4 External Recirculation with NaviCirc
The following pump models are recommended for use with the
NCB-H boiler and DHW recirculation systems.
When using the indicated pump models, observe the following
maximum recirculation pipe lengths:
●
100 feet (30 m) equivalent length of
1
/
2
” copper pipe
●
400 feet (120 m) equivalent length of
3
/
4
” copper pipe
External Recirculation Mode
For best performance, select the Intelligent or Weekly option in the
External recirculation DHW recirculation menu. To use the aquastat
mode, install an aquastat to the DHW pipe line and connect to the
CNC6 terminal on the PCB. (Refer to “3.7.4 Wiring Diagram - Zone
Pump System with DHW Recirculation” in the NCB-H Installation &
Operation Manual.)
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 ”2.3.1 Setting the DHW Operation” on page 54 for
details.
N
A/H
DHW PRI
L N L
N L
N L N L
Z3Z2Z1
N
A/H
DHW PRI
L N L
N L
N L N L
Z3Z2Z1
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_Recir
COM NO NC
ZONE_V/V3
COM NO NC
ZONE_V/V2
COM NO NC
ZONE_V/V1
City Water
Supply
Check
Valve
N
A/H
DHW PRI
L N L
N L
N L N L
Z3Z2Z1
N
A/H
DHW PRI
L N L
N L
N L N L
Z3Z2Z1
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_Recir
COM NO NC
ZONE_V/V3
COM NO NC
ZONE_V/V2
COM NO NC
ZONE_V/V1
* Recirculation
Pump
NaviCirc
DHW Supply
Return Water
Expansion Tank
Recirculation
Pump
(max. 2.5 A)
Neutral
(N)
Line
(L)