Navien NCB300-28K, Service Manual

Page: 35 / 108

34 System Details
Item Description
3. 3 Way Valve
Test the 3 way valve operation.
●
The 3 way valve is turned on
as soon as you enter the test
mode.
●
Press the Plus button ( )
or the Minus button ( ) to
toggle the valve operation
[On (DHW) -> Off (CH)/Off
(CH) -> On (DHW)].
4.4.7.3 Setting the Special Operation Modes
To Set the boiler’s operation parameters, press the ECO button
( ) and Menu button ( ) simultaneously 5 seconds, and
then select “3. OPR”
5sec
Press the Plus button ( ) or the Minus button ( ) to switch
between the operation modes. Press the ECO button ( ) to
select an operation mode.
The boiler resumes operation in normal operation mode if no
input is detected for 3 hours.
Press the Info button ( ) to return to the previous screen or
menu.
Item Description
oPE.0 (Normal)
Set the boiler to run in normal
operation mode.
oPE.1 (Min)
Set the boiler to run in
minimum operation mode.
oPE.2 (CH MAX)
Set the boiler to run in central
heating maximum operation
mode.
oPE.3 (DHW MAX)
Set the boiler to run in DHW
maximum operation mode.
4.4.7.2 Diagnosing the Boiler System
To Set the boiler’s operation parameters, press the ECO button
( ) and Menu button ( ) simultaneously 5 seconds, and
then select “2. TST”
5sec
Press the Plus button ( ) or the Minus button ( ) to switch
between the test procedures. Press the ECO button ( ) to run
a test procedure.
Note
During the test mode, the boiler stops combustion.
Press the Info button ( ) to return to the previous screen or
menu.
Item Description
1. Fan Motor
Test the fan operation.
From a stopped state, the fan
speed gradually increases and
reaches the maximum speed
at 6500 RPM, and then the fan
speed decreases until the fan
stops operating.
Note
Except for the Power
button ( ), the
buttons do not work
during fan motor test
mode.
2. Boiler Pump
Test the boiler pump operation.
On (10 seconds) -> Off (5 seconds)
-> On (10 seconds) for 5 boiler
pump operation cycles
Note
Except for the Power
button ( ), the
buttons do not work
during boiler pump
test mode.