39
classic m -
Installation & Servicing
FAULT FINDING
F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING
63 L....8..... (FAN)
64 H.....1..... (FLOW TEMPERATURE)
YES
Is there continuity between the
PCB and the thermistor ?
Check resistance. The sensors can be checked
by measuring their resistance, using a suitable
multimeter connected across the sensors'
terminal pins
At 25
0
C
expect
9,700-10,300 Ohms
At 60
0
C
expect
2,400-2,600 Ohms
At 85
0
C
expect
1,000-1,100 Ohms
Remove the boiler control thermistor from the
CH flow pipe and disconnect thermistor wires
Are the thermistor values correct ?
Replace the thermistor
NO
NO
YES
Replace PCB
Check and replace wiring as necessary
65 H......F........ (FLAME DETECTION - SHORT CIRCUIT)
Replace detection electrode
Is there continuity between the detection
electrode terminal at the PCB and earth ?
Check the detection electrode for
continuity and visual condition.
Replace if necessary.
NO
YES
66 H......n........ (PHASE REVERSAL)
Check wiring to the boiler for
reversed live and neutral
Is nominal 330 V DC present
across red and blue at the fan
connector as reset button is
pressed?
Replace fan
YES
NO
Replace harness
Replace PCB
YES
Is 14V DC present
across yellow and pink
at the fan connector?
Check wiring harness for continuity.
Is there continuity?
NO
YES
NO
Содержание Classic m3050
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