Navien NCB-190/060H, Руководство по установке и эксплуатации

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76 Installing a Cascade System
Note
●
The recommended recirculation
flow rate for each water heater is 2-4
GPM. Depending on the number
of water heaters and the diameter
of the recirculation line, it may not
be necessary to connect all the NPE
“A2” series water heaters to the
recirculation line. If this is the case, set
any unconnected “A2” model water
heaters to Internal Recirculation Mode.
●
For any NPE “A2” water heater that is
connected to the recirculation line,
each individual unit must be set to the
proper recirculation mode utilizing
the 2-way valve and front panel
DIP switches. Refer to the NPE-A2
Installation Manual for additional
details.
Note
●
System application drawings are
intended to explain the system piping
concept only.
●
Install a NaviClean Filter in the system
heating return to remove foreign
objects from the system. Foreign
objects inside the system may result in
abnormal system operation.
●
Refer to “3.4 Filling the System”
on page 29 for make-up water
connections and refer to the
requirements of your local codes to
ensure compliance.
●
Use pumps with integral check valves
or install check valves at the pump
outlets.
●
Adjust the settings at the main unit as
the cascade system uses only the main
unit settings. Changes made to the
sub units are ignored.
●
Each unit must be configured for
cascade operation.
●
When linking multiple water heaters to NCB-H
combi-boiler, only the main unit can provide
space heating and sub units must be configured
for DHW only (You can set only the NCB-H combi-
boiler as the main unit in the cascade system, and
the main unit controls the power on/off status of
all the sub units in the system).
●
Once turned on by the main unit, the water
heaters will operate in stages to satisfy the DHW
demands.
●
After completing the cascade settings and saving
the changes, the boiler and water heater units
must be turned off then turned back on for the
changes to take effect.
●
If errors occur while operating a cascade system,
the relevant errors are displayed in the display of
the failing unit.
●
Power supply to the units must be OFF during the
system piping.