Appendixes 55
11. Replace the gas inlet pipe to its original position and use all
screws to secure all connections.
Note
Do not overtighten as this may damage or crack
the components.
12. Check the labels carefully and then connect all the wires.
13. Set the front panel Dip Switch to change the gas type.
WARNING
Ensure that you have turned off the power to the boiler
before accessing the DIP switches.
1 2
3
4 5 6
7 8
O
N
Switch Function
Setting
1 & 2
Fuel
Selection
G20 (LNG)
1-OFF, 2-OFF
G25, G27(LNG)
1-OFF, 2-ON
G30 (LPG)
1-ON, 2-OFF
G31 (LPG)
1-ON, 2-ON
DANGER
●
When conversion is required, be sure to set the front panel
DIP switches according to the supply gas type.
●
Failure to properly set the DIP switches could cause
carbon monoxide poisoning, resulting in severe personal
injury or death.
14. Turn on the gas and water supply to the boiler.
15. 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 8.
b. Insert the analyzer into the port (Figure 8).
Figure 8. Insert the Analyzer
Model
Gas Type
Max
Min
%CO
2
%CO
2
NCB-24LSWE
G20
9.2% ± 0.5%
8.6% ± 0.3%
G31
10.4% ± 0.5%
10.0% ± 0.3%
NCB-28LSWE
G20
9.2% ± 0.5%
8.6% ± 0.3%
G31
10.4% ± 0.5%
10.0% ± 0.3%
NCB-34LSWE
G20
9.2% ± 0.5%
8.6% ± 0.3%
G31
10.4% ± 0.5%
10.0% ± 0.3%
NCB-40LSWE
G20
9.2% ± 0.5%
8.6% ± 0.3%
G31
10.4% ± 0.5%
10.0% ± 0.3%
Table 2. CO
2
value
(CO
2
values for high fire must be within 0.5% and CO
2
values
for low fire must be within 0.3%of the values listed.)
