Viessmann VITODENS 333 Service Instructions Manual page 26

Initial start-up, inspection, maintenance
Further details regarding the individual steps
Checking all gas equipment for soundness at operating pres-
sure
Danger
Escaping gas leads to a risk of
explosion.
Check gas equipment for
soundness.
Checking the ionisation current
A Adaptor line (available as acces-
sory)
26
(cont.)
1. Pull the line off and connect test
equipment (adaptor line available
as accessory).
2. Set the upper rated output.
Constant temperature control unit:
Press K and d simultaneously
&
for at least 2 seconds.
With a/b in the display, select
&
2.
Weather-compensated control unit:
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 4 µA as soon as
the flame is established (approx. 2-
3 seconds after opening the gas
combination valve).
3. If the ionisation current is < 4 µA
&
Check the electrode gap, see
page 21.
&
Check the control unit power sup-
ply.