67
3.
Compare the test result with the actual tempera-
ture. For calling up the actual temperature, see
chapter "Diagnosis".
In the case of severe deviation, check sensor
installation and replace the sensor if required.
Lambda probe
For measuring the residual oxygen content in the flue
gas.
Checking the Lambda probe
Danger
Risk of burns from hot components.
Switch off the boiler and let it cool down.
1.
Remove the Lambda probe.
Note
The Lambda probe is located on the back on the
boiler, under the secondary air damper. See
page 41
2.
Check the Lambda probe for contamination and
damage.
3.
Check the connecting cable for damage.
Notes
■
Do not paint, wax or treat the probe with any other
such substance. Only use special grease recommen-
ded for Lambda probes to grease the threads.
■
Do not solder the connecting cable; it must be crim-
ped, clamped or secured with screws.
Connection
The Lambda probe is connected with plug
a:K
(see
chapter "Connection and wiring diagram", page 96).
Calibrating the Lambda probe
Note
The Lambda probe can only be calibrated manually.
Requirements:
■
Boiler not in operation
■
Flue gas temperature < 50 °C
1.
Disconnect the Lambda probe plug and remove
the probe from the flue pipe. Insert the probe
again.
2.
Call up the service menu on the control unit.
Probe heating is activated automatically.
3.
Hang the probe outside the boiler for at least 5
minutes.
4.
Use
|
/
~
to select
"Service functions"
. Confirm
with
d
.
5.
Use
|
/
~
to select
"Calibrate O2 probe"
. Con-
firm with
d
.
6.
Use
|
/
~
to select
"Yes"
. Confirm with
d
.
Note
Probe is calibrated correctly if 21 % O
2
is dis-
played.
7.
Danger
A hot Lambda probe may cause burns
Wear safety gloves.
Install the probe in the flue pipe.
Maintenance
Sensors
(cont.)
5777 985 GB
Maintenance
