Codes - Viessmann Vitocrossal CRU 800 Service Instructions For Contractors

Troubleshooting
Fault codes with display on burner control unit
Displayed fault System characteristics
code
F F9 No feedback from fan
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
Detailed error codes for F FD
Detailed er- Component/signal Cause of fault
ror code
30 Reset button
31 Fuel valve 2 feed-
back
32 Air pressure switch
1
42
Cause
External fan power supply
not connected, faulty or
defective. If voltage is
present at connected plug
" a-Ö " and the fan does
not start up when plug
" A" is disconnected,
a-Ö
there is a fault with the
fan. Cable "
a-Ö
broken.
Relay in the terminal box
does not switch.
Fan blocked (possibly by
foreign bodies).
Fan does not reach idle
state, cable "
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 con-
■
figured incorrectly
Cause
Internal system fault and
EMC
See the following table
Programming unit faulty
Wiring
Incorrect return voltage
(e.g. DC voltage)
Actuator faulty
High switching se-
quence, switch flutters
External voltage
(cont.)
Measures
Check cable"
power supply. Replace cable or
fan. Remove foreign bodies.
A" faulty or
Wind influence on fan; check flue
A" faulty, outlet and fan. Replace cable
a-Ö
" 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.
Measures
Reset burner control unit. Replace
the burner control unit if the fault
persists.
See the following table
Measure
Replace programming unit.
Check wiring.
Remove plug from fuel valve 2, reset burner con-
trol unit and check error messages. If F Fd recurs,
replace burner control unit. Otherwise, replace
fuel valve 2.
Check flue gas path and combustion. Check set-
ting LDW1. Check burner gauze assembly for
contamination.
A" and external
a-Ö