Viessmann VITOCROSSAL 200 Service Instructions Manual page 44

Troubleshooting
Diagnosis
(cont.)
Fault code System characteris-
tics
37 The fan does not
reach its set speed
42 Burner control unit
remains in start-up
position, no start in
spite of heat demand
4E Burner control unit
fault
Scrolling Constant start
display: 1 - attempt
2 - 3 - 4 - 5 -
7
Internal system fault
Internal system faults are created if a perfect program sequence can no longer be
guaranteed.
Fault code System characteris-
tics
01 and 02, Fault in the burner
04 to 15, control unit area
70 to 79,
7A, FF
FF Fault in the burner
control unit area
44
Cause
The fan is faulty;
cable "100" or
"100a" is faulty or
broken; the fan is
blocked by a for-
eign body
Safety chain inter-
rupted
Internal fault
Cores "L1" and
"N" at the power
supply terminals of
the control unit
interchanged
Cause
Internal system
fault
EEPROM
Measures
Check cable "100" or
"100a"; if required,
replace the cable or fan or
remove foreign bodies.
Check jumper B2 (plug
fJ) of safety chain at
burner control unit.
Replace burner control
unit.
Check the power supply
and swap the cores
Measures
Replace burner control
unit.
Have your system tested
for EMC interference.