Navien NFB-175H, Installation Manual, Page: 121 / 135

121 Appendixes
12. Measure and adjust the gas/air ratio.
Option 1. Using Combustion Analyzer
(recommended)
a. Remove the analyzer port’s cap.
b. Insert the analyzer into the port (Figure 7).
Figure 7. Insert the Analyzer
The DIP SW1 (Set of 6 Switches) on the circuit board
configures the operation status and model settings.
1 2 3 4 5 6
O
N
O
N
1 2 3 4 5 6 7 8
Switch Function Setting
1 & 2
Operation
Status
Normal
Operation
1-OFF, 2-OFF
2-stage MAX 1-ON, 2-OFF
1-stage MIN 1-OFF, 2-ON
1-stage MAX 1-ON, 2-ON
5 & 6
Model
Setting
NFB-200H 5-OFF, 6-OFF
NFB-175H 5-ON, 6-OFF
Note
●
This unit may be installed at elevations
up to 10,100 ft (3,078 m) for use with
natural gas and propane. To use the unit
at a specific altitude, the DIP switches
should be set as described above.
●
High Altitude: Above 2,000 ft (610 m), the
unit will de-rate by 3% for each 1,000 ft
(305 m) of altitude gain.
●
For Natural Gas, if you install the unit at
above 5,400 ft (1,646 m), it is required to
change the Gas Orifice for high altitude.
Be careful not to confuse it with the Gas
Orifice for Propane.
●
Note that the Gas Orifice from the
PROPANE CONVERSION KIT covers the
boiler’s installation at an altitude of 0 to
10,100 ft.
CAUTION
Ensure that the High Altitude setting reflects the
actual location of the boiler. If not, it may cause
personal injury or malfunction of the boiler.
DANGER
●
When conversion is required, be sure to
set the PCB DIP SW2 (Set of 8 Switches) #1
according to the supply gas type.
●
For NG, use the Gas Orifice for high altitude
when the boiler is installed at above 5,400 ft,
and be careful not to confuse it with the Gas
Orifice for LP.
●
For High Altitude conversion, check the DIP
switches setting value by altitude before
setting.
●
Failure to properly set the DIP switches could
cause carbon monoxide poisoning, resulting
in severe personal injury or death.
11. Turn on the gas and water supply to the boiler.