Repair manual

26
Fault diagnosis - flashing code
(LED with series resistor)
The electronic control unit can store up to five faults.
The function or type of fault is output by the control unit as a
flashing code and displayed by an LED (with series resistor).
The LED with series resistor is connected to the cable harness
of the HYDRONIC, using the 8-pin connector, pin 12, blue /
white cable 1 mm² (see wiring diagram page 25).
The remedial measures are described in the fault code tables
on pages 30 to 33 under the appropriate fault code.
Release of control unit when locked
With the HYDRONIC switched on, apply positive for approx. 3
seconds to the 8-pin cable harness connector, pin 13, yellow
/ red 1 mm² cable (external excitation of the water pump)
--> the control unit is unlocked.
Additional variant from control unit 25 1818 53 00 00
Apply positive for approx. 3 seconds to the 8-pin cable har-
ness connector, pin 9, blue / black 1 mm² cable (fault in Bus
2000 water pump) --> the control unit is unlocked.
4 / Troubleshooting
Drawing 20
Flashing code
Light duration - short pulse: 0,4 sec.
Light duration - long pulse: 2,0 sec.
Interval between the pulses: 0.4 sec.
Period of a flashing sequence: 8.0 sec.
400 ms interval at
start of flashing code
8 sec.
16 sec.
Operation without fault
Flame monitor
Fault code 16, 51, 58
Safety time overshoot
Fault code 50 , 52
Flame loss
Fault code 54
Overheating
Fault code 12, 15
Burner motor
Fault code 32, 33
Undervoltage cutout
Fault code 11
Overvoltage cutout
Fault code 10
Temperature sensor
Fault code 14, 60 ,61, 71, 72
Connection fault
Fault code 20, 21, 25, 37 - 39
44 - 49, 80 - 83
Control unit
Fault code 90 - 97