88 Appendices
Replace the old Orifice piece with the new part for use with LP
gas. Ensure that the Orifice is properly seated inside the port
before proceeding to the next step.
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
O
N
Figure 6. Set the DIP switches
Switch Function
Setting
1 & 2
Fuel
Selection
G20 (LNG)
1-OFF, 2-OFF
G30 (LPG)
1-ON, 2-OFF
G31 (LPG)
1-ON, 2-ON
Table 1. The DIP Switch Setting by Fuel Selection
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.
14. Turn on the gas and water supply to the boiler.
15. Measure and adjust the gas/air ratio.
a. Loosen the screw, rotate the plate and remove the
gasket to access the emissions monitoring port as
shown in Figure 7.
b. Insert the analyser into the port (Figure 7).
White Cap
(Air Supply)
Black Cap
(Exhaust Gas)
Figure 7. Insert the Analyser
Model
Gas Type
Max
Min
%CO₂
%CO₂
NCB700-
2S+/42K
G20
8.8%
8.8%
G31
10.4%
10.4%
NCB700-
3S/54K
G20
8.8%
8.8%
G31
10.4%
10.4%
Table 2. CO₂ Value
(CO₂ values for high fire must be within 0.5% and CO₂ values
for low fire must be within 0.3% of the values listed.)
