Viessmann VITOCROSSAL CRU 800 kW Service Instructions Manual page 41

Fault codes
(cont.)
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 80 Burner control unit in a fault
state; system cooling down;
burner control unit locked out.
F 81 Burner control unit in a fault
state
F 82 Burner control unit in a fault
state; system cooling down;
burner control unit locked out.
F 83 Burner control unit in a fault
state
F 88 Burner control unit in a fault
state
F 89 Burner control unit in a fault
state
F E3 Burner control unit in a fault
state
F EB Burner locked out
F EC Burner control unit in a fault
state
F ED Burner control unit in a fault
state
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" faulty or
a-Ö
broken.
Relay in the terminal box
does not switch.
Fan blocked (possibly by
foreign bodies).
Fan does not reach idle
state, cable " A" faulty,
a-Ö
fan faulty, burner control
unit faulty
Short circ., boiler temp
sensor
Sensor drift, boiler water
temperature sensor
Short circ., flue gas temp
sensor
Sensor drift, flue gas tem-
perature sensor
Lead break, boiler water
temperature sensor
Lead break, flue gas tem-
perature sensor
Safety equipment has re-
sponded.
Burner not enabled via ex-
ternal contact.
Internal error in feedback
from safety relay.
Internal error in feedback
from ignition relay.
Troubleshooting
Measures
Check cable" A" and external
a-Ö
power supply. Replace cable or
fan. Remove foreign bodies.
Wind influence on fan; check flue
outlet and fan. Replace cable
" A". Replace fan. Replace
a-Ö
burner control unit.
Check connecting cable and boiler
water temperature sensor 3A/3B
(dual sensor). Replace sensor if re-
quired.
Check connecting cable and boiler
water temperature sensor 3A/3B
(dual sensor). Replace sensor if re-
quired.
Check connecting cable and flue
gas temperature sensor 15A/15B
(dual sensor). Replace sensor if re-
quired.
Check connecting cable and flue
gas temperature sensor 15A/15B
(dual sensor). Replace sensor if re-
quired.
Check connecting cable and boiler
water temperature sensor 3A/3B
(dual sensor). Replace sensor if re-
quired.
Check connecting cable and flue
gas temperature sensor 15A/15B
(dual sensor). Replace sensor if re-
quired.
Check safety equipment on
STB/STB at plug of the
aBÖ
Vitotronic.
Check components connected to
TR/TR EIN at plug of the
aBÖ
Vitotronic.
Reset the burner control unit. Re-
place burner control unit if re-
quired.
Reset the burner control unit. Re-
place burner control unit if re-
quired.
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