Navien NHB Series, Installation & Operation Manual

Page: 103 / 135

103 Operating the Boiler
Item Description
2. System Off
Select this option on the main unit
of a cascade system to end cascade
operation.
Ɣ
Enter main setting mode to reassign
IDs and begin a cascade system
again.
Ɣ
If a sub unit has a network
communication problem, select this
option on the sub unit to exclude
the individual unit from the cascade
system.
3. Operation Strategy
Set the cascade strategy (control type).
Ɣ
Default: ECO
Note
For more detailed information
on the operation strategies,
refer to “Setting the Operation
Strategy” on page 105.
4. Vent Type
Set the ventilation type.
Ɣ
Setting range: Common/Individual
Ɣ
Default: Common
5. Initial Activating
Units
Set the number of initial activating
units in the cascade system.
Ɣ Setting range: 0 – 32
Ɣ Default: 0
Tap ( ) to go to the next page.
Item Description
1. Minimum
Operation Unit
Set the minimum number of the boilers
for the cascade system.
Ɣ
Setting range: 1 – 32
Ɣ
Default: 1
2. Unit On HC
Set the heating capacity standard when
adding boilers to the cascade system.
(Applied if Operation Strategy is set to
Custom .)
Ɣ Setting range: (Unit Off HC + 20%) -
(Max. Cascade heat - 5%)
Ɣ
Default: 70%
11.6.4 Configuring a Cascade System
To view and configure the cascade settings, tap the Set button
(
) > Cascade on the screen.
Item Description
1. Setting Mode
Ɣ To enter the Cascade Setting Mode,
tap
START .
Ɣ
The setting mode is entered and
the IDs of all boilers that can
communicate with the Main via
the RS485 communication line are
initialized.
Ɣ
The boilers whose IDs are initialized
by the Main are set to <Sub setting
mode>, if you press the OK button
for 3 seconds or more, the Main gives
you the ID and it is displayed on the
screen.
Ɣ
The Main periodically checks the
RS485 communication, and when
there is an ID request from the Sub,
the ID is sequentially incremented
and added to the Sub (1 to 31).
Ɣ
Tap OK in the Main to complete
the cascade setting. In the Main
and the Sub with assigned IDs, the
pop-up windows will be closed and
the cascade setting mode will be
completed.
Ɣ
The Home screen is automatically
changed into the cascade screen
as soon as the cascade setting is
complete.
Ɣ
In Main setting mode, if no input is
detected for 60 minutes, the boiler
resumes normal operation without
cascading.