Viessmann MatriX-Disk burner Service Instructions For Contractors page 41

Fault codes with display on burner control unit
Displayed fault System characteristics
code
F F8 Flame tears off during modu-
lation (burner output increa-
ses).
F F8 Flame tears off during modu-
lation (burner output decrea-
ses).
F F9 Fan not running; fan speed
not reached.
F F9 Status duration too long at
fan ramp-up
F F9 Fan speed deviation
F FA Fan runs without demand;
burner control unit in a fault
state.
F Fb Burner does not start.
Internal system faults: Displayed fault codes and detailed fault codes
Internal system faults will be shown if the correct pro-
gram sequence can no longer be guaranteed.
Displayed fault System characteristics
code
F E5, F EC, Fault in burner control unit
F ED, F FF area
F FD Fault in burner control unit
area
(cont.)
Cause
Air pressure switch 2 ad-
justed incorrectly.
A minimum output is un-
dershot due to dirt on the
burner gauze assembly or
air filter
No mains voltage, fan
faulty; cables faulty or bro-
ken
Internal fault; fan cannot
reach its set value.
Fan faulty, cable " A"
a-Ö
faulty or broken
Fan does not reach idle
state, cable " A" faulty,
a-Ö
fan faulty, burner control
unit faulty
Combustion chamber
■
pressure too high
(LDW2)
Condensate backed up
■
Flue gas path blocked
■
Flue gas damper does
■
not open or close.
Burner control unit incor-
■
rectly configured (with-
out flue gas damper),
see page 32.
Cause
Internal system fault and
EMC
See the following table
Troubleshooting
Measures
Adjust air pressure switch 2 (see
page 45).
Check the burner gauze assembly,
see page 24.
Clean the ionisation electrode; re-
place if required.
Clean the air filter.
Check cables. Check mains volt-
age. If the fan does not start with
mains voltage present and bus
plug a-Ö A disconnected, check
junction box, replace fan.
Replace fan or burner control unit.
Check cable. Replace cable
" A" or fan if necessary.
a-Ö
Wind influence on fan; check flue
outlet and fan. Replace cable
" A". Replace fan. Replace
a-Ö
burner control unit.
Check condensate drain and flue
■
gas path for blockages.
Check flue gas damper.
■
Check motorised flue gas damp-
■
er operating parameters.
Check air pressure switch 2, see
■
page 45.
Measures
Reset burner control unit. Replace
the burner control unit if the fault
persists.
See the following table
41