Checking The Combustion Quality - Viessmann VITODENS 242-F Installation And Service Instructions Manual

Further details regarding the individual steps

Checking the combustion quality

The electronic combustion controller
automatically ensures optimum combus-
tion quality. During commissioning/
maintenance, only the combustion val-
ues need to be checked. For this, meas-
ure the CO content and the CO
content. For a description of the elec-
tronic combustion controller functions,
see page 168.
Note
Operate the appliance with uncontami-
nated combustion air to prevent operat-
ing faults and damage.
CO content
■ The CO content must be < 1000 ppm
for all gas types.
CO or O content
2 2
■ The CO content must be within the
2
following limits for upper and lower
heating output respectively:
– 7.5 to 9.5 % for natural gas E and LL
– 8.8 to 11.1 % for LPG P
■ For all gas types, the O
be between 4.0 and 7.6 %.
If the actual CO or O
2
their respective ranges, proceed as fol-
lows:
■ Check the balanced flue system for
tightness, see page 58.
■ Check the ionisation electrode and
connecting cable, see page 61.
or O
2 2
content must
2
values lie outside
2
Commissioning, inspection, maintenance
(cont.)
Note
During commissioning, the combustion
controller carries out an automatic cali-
bration. Only test the emissions approx.
30 s after the burner has started.
1. Connect a flue gas analyser at flue
gas port A on the boiler flue con-
nection.
2. Open the gas shut-off valve, start the
boiler and create a heat demand.
3. Set the lower heating output (see
page 72).
4. Check the CO
2
actual value deviate from the afore-
mentioned ranges by more than 1 %,
implement steps on page 71.
5. Enter the actual values into the
report.
6. Set the upper heating output (see
page 72).
content. Should the
71