Diagnosis And Correction - Viessmann Vitotronic 300 Operating Instructions Manual

Troubleshooting guide

Diagnosis and correction

DFault
Tu
Boiler sensor
U
Acknowledge? Yes
26
If a fault occurs on the heating system, it will be indicated in the display win
dow and by the flashing red fault lamp (see page 5).
Using the scan facility, you can read off the fault code yourself and inform
°C
your heating contractor accordingly.
1. Open the hinged cover on the pro
gramming unit.
2. c Press c for fault search.
The error source is dis
played in plain language
and in the form of a fault
code.
3. d Press d; the display
changes to "Acknow
ledge? Yes".
4. a/b Press a/b for "Yes" or
"No".
5. d Press d to confirm;
the display changes and
shows the boiler tempe
rature.
6. Close the hinged cover on the pro
gramming unit.
To call up an acknowledged fault message
1. d Press d for approx.
2 seconds.
2. a/b Press a/b to display
further faults.
Example
U
Fault display
Error number
Sensor designation
plug designation
Open circuit
or
Short circuit
Press "Acknowledge?" to confirm
that you have noted the fault.
Please note:
The fault message will re-appear at
7.00 hrs on the following day if the
fault is not corrected in the mean
time.
The red fault lamp continues to
flash until the fault has been cor
rected.
The fault is displayed.
Only if two or more faults have
occurred.