Bosch Worchester GREENSTAR ZWB 7-27 HE combi - Page 30

6 720 610 576 GB (02.05)
30
Converting the appliance to different gas types
B Turn the temperature control until the display
shows 2.
(= max. rated heat output).
The display and the button will flash.
Fig. 43
B Measure the CO
2
level.
B Prise off the seal on the gas flow restrictor.
B Adjust the gas flow restrictor (63) to obtain the CO
2
level given in Table 15. Refer to fig. 44.
Fig. 44
B Measure the CO level.
If the CO level is over 300 ppm, the gas volumetric
flow rate is too high. Reduce the gas flow rate on the
adjustable gas flow restrictor (63) until the CO level
is below 100 ppm.
B Re-adjust the CO
2
level if necessary.
B Turn the temperature control anti-clockwise until
the display shows 1. (= min. rated heat output).
The display and the button will flash.
Fig. 45
B Measure the CO
2
level.
B Remove the seal from the gas valve adjusting screw
(64) and adjust the CO
2
level to the figure given in
Table 15 for min. rated heat output.
Fig. 46
B Measure the CO level.
If the CO level is over 300 ppm, the gas volumetric
flow rate is too high. Reduce the gas flow rate on the
adjustable gas flow restrictor (63) until the CO level
is below 100 ppm.
B Re-adjust the CO
2
level if necessary.
B Recheck the levels at min. and max. rated heat output
and re-adjust if necessary.
B Turn the temperature control anti-clockwise as
far as the stop so that the display shows 0.
(= Normal operating mode).
The display and the button will flash.
B Press and hold the button until the display
shows [ ].
B Reset the temperature controls and to their
original positions.
The display will revert to the CH flow temperature.
B Remove testing probe from the flue gas testing point
(234) and refit sealing plug.
B Re-seal gas valve adjusting screw and gas flow
restrictor.
B Replace outer case and secure.
Gas Type
CO
2
reading
at max.
rated heat
output
CO
2
reading
at min. rated
heat output
Natural gas type
H (23)
9.5 % 9.2 %
LPG
(propane)
11.3 % 11.0 %
Table 15
6 720 610 332-61.1O
63
6 720 610 332-64.1R
6 720 610 332-63.1O