Viessmann Vitotwin 300-W Installation And Service Instructions For Contractors page 132

Troubleshooting
Fault messages
Fault mes- Cause
sage
"298: False The Eng burner ionisation
flame Eng electrode has detected a
bu" faulty flame.
"299: False The auxiliary burner ionisa-
flame supp tion electrode has detected a
bu" faulty flame.
"300: Eng Stirling head control temper-
head undert ature too low.
SW"
132
(cont.)
Remedy
Check the gas supply. Check
gas type setting (see
page 66).
Check electrodes (see
page 73).
Check function of gas train
and ignition transformer.
Check balanced flue system.
Ensure that flue gases are
not being recirculated.
If the fault has not been rec-
tified, replace the control unit
PCB (see page 138).
Check thermocouple cables.
If the fault has not been rec-
tified, replace the control unit
PCB (see page 138).
Re-
set-
ting
AR
UR