107
Appendixes
12. Measure and adjust the gas/air ratio.
Option 1. Using Combustion Analyzer (recommended)
a. Loosen the screw, rotate the plate and remove the gasket
to access the emissions monitoring port as shown in
Figure 6.
b. Insert the analyzer into the port (Figure 6).
Figure 6. Insert the Analyzer
The DIP SW 1 on the circuit board configures the operation status
and model/capacity 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
3 & 4
Reserved
-
-
5 & 6
Model
NFC-200
5-OFF, 6-OFF
NFC-175
5-ON, 6-OFF
Model
Altitude
Fuel
High fire
Low fire
%CO
2
%CO
2
NFC-175
NFC-200
0-5,399 ft
NG
8.9
9.5
LP
10.2
10.8
5,400-10,100 ft
NG
8.5
9.5
LP
10.2
10.8
Table 2. CO
2
value
(CO
2
values must be within 0.5% of the values listed.)
Summary of Contents for NFC-175
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