Viessmann MatriX radiant burner Service Instructions Manual page 26

Initial start−up, inspection and maintenance
Gas burner control unit
Fault memory
The last six faults are saved and may be called up.
The order of scans ranges from the last to the previous fault codes.
The fault memory display will be terminated, if no key is pressed within
20 seconds.
Operating display
Status Service
Status Service
Operating display
26
(cont.)
Simultaneously press the reset button and key a.
Last fault
Press key S
Press key S
Sixth fault
Press key S