Fault Codes With Display On Burner Control Unit - Viessmann Vitocrossal CRU 800 Service Instructions For Contractors

Fault codes with display on burner control unit

General process errors: Displayed fault codes
Note
Carry out measures in the order described.
Each fault message is saved in the fault memory. The
10 most recent fault messages can be called up.
Displayed fault System characteristics
code
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 B7 Burner control unit in a fault
state; system cooling down;
burner control unit locked out.
F B7 Type of coding card
F E3 Burner control unit in a fault
state
F E4 Burner shuts down.
Cause
Short circuit, boiler water
temperature sensor
Sensor drift, boiler water
temperature sensor
Short circuit, flue gas tem-
perature sensor
Sensor drift, flue gas tem-
perature sensor
Lead break, boiler water
temperature sensor
Flue gas temperature sen-
sor disconnection
Coding card not inserted
in the burner control unit;
incorrect or faulty coding
card
Coding card does not
match burner control unit.
Safety equipment has re-
sponded.
Multiple detection of un-
dervoltage with recurrence
and renewed undervolt-
age
Troubleshooting
Measures
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.
Insert coding card. Check coding
card. Replace if necessary.
Replace coding card or burner
control unit.
Danger
Plug-in terminals on the
burner control unit are live.
Only replace the coding card
when the burner control unit
has been isolated from the
power supply.
Check safety equipment on
STB/STB at plug of the
aBÖ
Vitotronic.
Check the power supply.
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