Testing Combustion Air/Flue Gas At Set Heat Output; Testing The O - Worcester ZWBR 7-28 HE plus Installation And Servicing Instructions

ZWBR 7-28
CO
at max.
rated heat
Gas Type output
Natural gas type
LPG
Table 15
ZWBR 11-35
CO
Gas Type min. rated heat output
Natural gas type
LPG (Propan)
Table 16
y 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 at ZWBR 7-28
– below 200 ppm at ZWBR 11-35.
y Re-adjust the CO level if necessary.
2
y On the text display unit, select in the main menu Set-
tings, Service, Display service parameters.
y Press and hold the
onds) until the display shows Adjust service
parameters and the first service function to be set,
2.0, Operating mode.
y Select operating mode Min.
y Measure the CO level.
2
y Remove the seal from the gas valve adjusting
screw (64) and adjust the CO
given in Table 15 for min. rated heat output. Refer to
fig. 41.
Fig. 41
y 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
6 720 610 597 GB (01.07)
reading
2
CO reading
2
at min. rated
heat output
9.5 % 9.2 %
11.3 % 11.0 %
reading at max. and
2
9.2 %
11.0 %
button (for about 5 sec-
level to the figure
2
Converting the appliance to different gas types
adjustable gas flow restrictor (63) until the CO level
is:
– below 100 ppm at ZWBR 7-28
– below 200 ppm at ZWBR 11-35.
y Re-adjust the CO level if necessary.
2
y Recheck the levels at min. and max. rated heat output
and re-adjust if necessary.
y On the text display unit, select in the main menu Set-
tings, Service, Display service parameters.
y Press and hold the
onds) until the display shows Adjust service
parameters and the first service function to be set,
2.0, Operating mode.
y Select operating mode Normal.
y Remove testing probe from the flue gas testing
point (234) and refit sealing plug.
y Re-seal gas valve adjusting screw and gas flow
restrictor.
y Replace the outer case by locating it on the top lugs
and pushing backwards until the bottom clips are
fully engaged. Check that the case is properly
aligned with facia. Refer to fig. 12.
y Secure by replacing the screw at the right-hand side.
Refer to fig. 12.
8.2 Testing combustion air/flue gas at
set heat output
8.2.1

Testing the O

2
tion air
By testing the O
i
bustion air the gas tightness of a type C
or C flue system can be checked. The
33
O level must not be less than 20,6 %.
2
The CO level must not exceed 0,2 %.
2
y Press and hold the
shows – –.
"Chimney sweep" mode is now active.
The button will light up and the display shows the
CH flow temperature.
In "chimney sweep" mode, the appliance
i
switches to max. rated heat output or the
set heating output. You then have 15 min-
utes in which to measure the levels. After
that, the appliance switches back from
"chimney sweep" mode to normal mode.
y Remove sealing plug from combustion air testing
point (234.1, Fig. 42).
button (for about 5 sec-
or CO level in the combus-
2
or CO level in the com-
2 2
13
button until the display
35