60 Appendices
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
%CO
2
%CO
2
NCB500
G20
8.80 %
8.35 %
G31
10.25 %
10.10 %
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.)
c. Fully open several hot water fixtures and set the boiler
to operate, and proceed Gas Setup Wizard.
Note
For proceeding Gas Setup Wizard for gas type
selection, refer to “10.3 Start-Up Wizard” on
Measure the CO
2
value at low fire.
If the CO
2
value is not within 0.5% of the value listed in
Table 2, the gas valve set screw will need to be adjusted.
If adjustment is necessary, locate the set screw as shown
in Figure 8. Using a T15 Hexalobular wrench, turn the
set screw no more than
1
/
4
turn clockwise to raise or
counterclockwise to lower the CO
2
value.
Figure 8. Set Screw Location
Note
The set screw is located behind the screw-on
cover. This must be removed first.
d. After Gas Setup Wizard is done, operate at minimum
mode.
Note
For operation mode selection, refer to “10.7.5
Setting the Special Operation Modes” on
e. Fully open several hot water fixtures and set the boiler
to operate at DHW maximum mode (refer to “10.7.5
Setting the Special Operation Modes” on page 50).
Measure the CO
2
value at high fire.
If the CO
2
values do not match Table 2 at high fire,
do not adjust the gas valve. Check for the proper Gas
Orifice.
DANGER
Improper gas valve settings can cause severe personal injury
or substantial property damage.
