Viessmann Vitodens 300 Service Instructions Manual page 23

Further details regarding the individual steps
Checking the ionisation current
A Adaptor line (available as acces-
sory)
B Control unit cable
Initial start-up, inspection, maintenance
(cont.)
1. Remove the cable and connect the
test equipment.
2. Set the upper rated output.
Constant temperature control units:
Press K and d simultaneously
&
for at least 2 seconds.
With a/b in the display, select
&
2.
Weather-compensated control
units:
Press K and d simultaneously
&
for at least 2 seconds.
With a/b in the display, select
&
"Full load".
Note
The minimum ionisation current
should be at least 5 µA as soon as
the flame is established (approx. 2 -
3 seconds after opening the gas
train).
3. If the ionisation current is < 5 µA\;
&
Check the electrode gap, see
page 19.
&
Check the control unit power sup-
ply.
4. After testing, press d.
5. Record the actual value in the ser-
vice report.
23