System Shutdown - Viessmann Vitocrossal 300 Service Instructions Manual

Further details regarding the individual steps
1. Switch OFF the control unit
ON/OFF switch.
2. Pull plug C of the ionisation
current lead off the ionisation
electrode.
3. Switch ON the system ON/OFF
switch.
There must be a fault shutdown
after two burner start attempts.
Display A flashes fault code F 25.
4. Switch OFF the system ON/OFF
switch.
Please note:
Test cable no. 1 is required when
checking with Testomatik−Gas.
You can also carry out this check with
a multimeter.
5. Push plug C of the ionisation
current lead into adaptor D.
6. Plug socket B of the test cable
onto the ionisation electrode.

System shutdown

1. Switch OFF the system ON/OFF
switch and the mains electric
supply and safeguard against
unauthorised reconnection.
Initial start−up, inspection and maintenance
7. Switch ON the system ON/OFF
switch and check the ionisation
current at the upper and lower
rated output.
For settings of the upper and
lower values, see page 26.
Please note:
Ionisation current at
H upper rated output
H lower rated output
8. Record the actual values in the
service report (see from page 46).
9. Switch the system ON/OFF switch
OFF , remove the test equipment
and reconnect the plug connector
of the ionisation current cable.
Please note:
The strength of the ionisation
current can also be shown in the
burner control unit display.
For this, simultaneously press
keys a and S on the burner
control unit. Under status, the
following is shown in the display:
"1, 2 or 3".
Meaning of display (strength of
the ionisation current):
1 = weak
2 = medium
3 = good.
2. Pull plug connectors fA and lÖ
off the burner control unit A (see
page 16).
3. Close the gas shut−off valve.
(cont.)
min. 10 mA,
min. 3 mA.
15