Viessmann CU3, Service Instructions Manual

Page: 15 / 56

15
Initial start−up, inspection and maintenance
Further details regarding the individual steps
(cont.)
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 twoburner start attempts.
Display
A
flashes fault codeF 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.
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 page26.
Please note:
Ionisation current at
H
upper rated output min. 10
m
A,
H
lower rated output min. 3
m
A .
8. Record the actual values in the
service report (see from page46).
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.
System shutdown
1. Switch OFF the system ON/OFF
switch and the mains electric
supply and safeguard against
unauthorised reconnection. 2. Pull plug connectors
fA
and
lÖ
off the burner control unit
A
(see
page16).
3. Close the gas shut−off valve.
5692500GB