Bosch ZWB28-3A - Page 77

Gas type conversion | 77
6 720 643 068 (2011/06)Copyright (optional information)
B On the gas throttle, break the seal at the slot and
remove the cap.
Fig. 70 Remove seal from the gas throttle
B Adjust the gas throttle to match the CO
2
or O
2
level for
maximum nominal output according to table 30.
Fig. 71 Set CO
2
or O
2
level for maximum nominal output
B Briefly press the emissions test button .
The display shows the supply temperature in
alternation with = minimum nominal output.
B Measure the CO
2
or O
2
level and the CO content of the
flue gas (Æ Section 12).
B Remove the sealed screw (Æ Fig. 72, [3]) from gas valve
adjustment screw (Æ Fig. 72, [2]) and set CO
2
or O
2
level for minimum nominal output.
Fig. 72 Set CO
2
or O
2
level for minimum nominal output
B Re-check settings at maximum and minimum nominal
output and re-adjust if necessary.
B Repeatedly press the emissions test button until the
light goes out.
The display returns to the supply temperature.
B Record the CO
2
or O
2
levels and the CO content of the
flue gas in the commissioning log.
B Reinstall the screw (Æ Fig. 72, [3]) to cover the gas
valve adjustment screw.
B Remove flue gas probe and close the flue gas test port
properly.
Fig. 73 Close flue gas test ports
Maximum
nominal output
Minimum
nominal output
Gas type CO
2
O
2
CO
2
O
2
NG 9.4 % 4.0 % 8.6 % 5.5 %
LPG (propane) 11.0 % 4.2 % 10.4% 5.1 %
Tab. 30 CO
2
or O
2
values at maximum and minimum nominal
output
1 .
2 .
6 7 2 0 6 1 2 6 5 9 - 3 7 . 1 R
6 7 2 0 6 1 2 6 5 9 - 3 8 . 1 R
6 720 641 933-81.1O
1
3
2
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