Vaillant ecoTEC plus 937, Instructions And Maintenance Instructions, Page: 57 / 64

57 Installation and maintenance instructions ecoTEC plus 0020031552_03
9.11 Checking and setting the CO
2
content, if re-
quired (air ratio adjustment)
h
Note
Checking/adjusting this value is only required
under the following circumstances: Replacing
the gas valve, converting from or to natural
gas/propane during an annual service (if a flue
gas analyser is available) or under suspicion of
faulty combustion!
• Remove the front cover.
• Press the "
- " and " + “ buttons simultaneously.
The "full load mode" is activated.
• Wait at least 5 minutes until the appliance reaches its
operating temperature.
2
1
Fig. 9.11 Measurement of the CO
2
content; Preparation air fig-
ure setting
• Measure the CO
2
content at the flue gas analysis
point ( 1 ) of the flue adapter.
• If required, remove the screw and swing the air inlet
pipe downwards through 90° (do not remove!).
• If necessary, set the corresponding flue gas value
(value with removed appliance front, see Table 9.2) by
turning the screw (
2 ).
-> Turn to the left: Higher CO
2
content
-> Turn to the right: Lower CO
2
content
h
Note
Only for natural gas:
Carry out the setting only in steps of 1/8 turn.
After each setting wait for approx. 1 Minute
until the value has stabilised.
Only for liquid gas:
Carry out the setting only in very small steps
(approx. 1/16 turn.) After each setting wait for
approx. 1 Minute until the value has stabilised.
• Swing the air inlet pipe upwards again.
• Check the CO
2
content again.
• If necessary repeat the setting procedure.
• Press the "i“ and "+“ buttons simultaneously.
The "full load mode" is de-activated. Deactivation of
the full load mode if no button is pushed within a peri-
od of 15 minutes.
• Secure the air inlet pipe.
• Re-fit the front cover.
Settings: Natural
gas (H) To-
lerance
Propane To-
lerance
Unit
CO
2
content after 5 min.
Full load mode with
front cladding closed
9.2
±
1.0 10.2
±
0.5 Vol.–%
CO
2
content after 5 min.
Full load mode with
front cladding removed
9.0
±
1.0 10.0
±
0.5 Vol.–%
Setting for the
Wobbe-Index W0 15 22.5 kWh/m 3
CO content in full load
mode < 250 < 250 ppm
Table 9.2 Factory gas settings
Replacing components 9