Worcester benchmark ZWB 7-25 R 25 HE Design, Installation And Servicing Instructions page 31

B Turn the temperature control
shows 2. (= max. rated heat output).
The display and the
6 720 610 332-61.1O
Fig. 44
B Measure the CO level.
2
B Prise off the seal on the gas flow restrictor.
B Adjust the gas flow restrictor (63) to obtain the CO
level given in Table 15. Refer to fig. 45.
Fig. 45
CO
at max. rated
Gas Type heat output
Natural gas type 9.2 %
G20
LPG G31 10.8 %
(propane)
Table 15
B Turn the temperature control
the display shows 1. (= min. rated heat output).
The display and the
6 720 610 332-63.1O
Fig. 46
B Measure the CO
level.
2
6 720 611 441 GB (03.11)
until the display
button will flash.
63
6 720 610 332-64.1R
CO reading
2
reading at min.
2
rated heat
output
8.8 %
10.5 %
anti-clockwise until
button will flash.
Converting the appliance to different gas types
B Remove the seal from the gas valve adjusting
screw (64) and adjust the CO
given in Table 15 for min. rated heat output.
2
3928-74.1R
Fig. 47
B Recheck the levels at min. and max. rated heat output
and re-adjust if necessary.
B Turn the temperature control
far as the stop so that the display shows 0.
(= Normal operating mode).
The display and the
B Press and hold the
shows [ ].
B Reset the temperature controls
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.
level to the figure
2
64
anti-clockwise as
button will flash.
button until the display
and to their
31