Testing Combustion Air/Flue Gas At Set Heat Output; Testing The O; Testing Co And Co; Maintenance - Benchmark ZWB 7-29 CC1 Installation And Servicing

7.2 Testing combustion air/flue gas at
set heat output
7.2.1

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
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O level must not be less than 20,6 %.
2
The CO level must not exceed 0,2 %.
2
B 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.
B Remove sealing plug from combustion air testing
point (234.1, fig. 49).
B Insert testing probe about 80 mm into the testing
point and seal testing point.
Fig. 49
B Measure O
and CO
2 2
B Refit sealing plug.
B Press and hold
button until the display shows – –.
The button will stop flashing and the display
shows the CH flow temperature.
7.2.2

Testing CO and CO

B Press and hold the
shows – –.
"Chimney sweep" mode is now active.
The button will light up and the display shows the
CH flow temperature.
6 720 610 599 GB (03.02)
or CO level in the combus-
2
or CO level in the com-
2 2
13
button until the display
levels.
2
button until the display
You have 15 minutes in which to measure
i
the levels. After that, the appliance switch-
es back from "chimney sweep" mode to
normal mode.
B Remove sealing plug from flue gas testing point
(234, Fig. 49).
B Insert testing probe about 135 mm into the testing
point and seal testing point.
B CO- and CO
levels.
2
B Refit sealing plug.
B Press and hold
button until the display shows – –.
The button will stop flashing and the display
shows the CH flow temperature.
8

Maintenance

B Always disconnect the appliance from
the electrical power supply (fuse, circuit
breaker) before carrying out any work on
the electrical systems or components.
B Always turn off the gas cock before car-
rying out any work on components
which carry gas.
There is a special Service booklet for the
i
Engineer, order no. 7 181 465 346, avail-
able to competent persons.
All safety and control systems are moni-
i
tored by the Bosch Heatronic. In the event
of a component fault, the display shows a
fault code.
B The User should be recommended to have the appli-
ance serviced regularly by a competent person (see
Maintenance Contract).
B Use only genuine spare parts
B Refer to the Spare Parts List when ordering spare
parts.
B Always renew seals and O-rings removed during
servicing or repair work.
B Use only the following types of grease:
– Water valve: WRAS approved silicon based
grease
– Unions: approved sealant.
B To drain the appliance shut the system valves and
open the pressure relief valve.
B Upon completion of any electrical work check for
earth continuity, correct polarisation and resistance
to earth.
Maintenance
33