47
icos system condensing -
Installation and Servicing
F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING
FAULT FINDING
80 H......4....... (FLUE SENSOR)
Check wiring for continuity from the
PCB to the flue thermistor
Can the fault condition be reset by switching off
the mains supply to the boiler ?
Is the system filled and vented and all
isolation valves open ?
NO
YES
Check resistance. The sensors can be
checked by measuring their resistance, using
a suitable multimeter connected across the
sensors' terminal pins
At 25
o
C
expect
9,700-10,300 Ohms
At 60
o
C
expect
2,400-2,600 Ohms
At 85
o
C
expect
1,000-1,100 Ohms
Are thermistor values correct ?
Replace PCB
Replace thermistor
Fill and vent the
system and open all
isolating valves
YES
Check resistance. The sensors can be
checked by measuring their resistance, using
a suitable multimeter connected across the
sensors' terminal pins
At 25
o
C
expect
9,700-10,300 Ohms
At 60
o
C
expect
2,400-2,600 Ohms
At 85
o
C
expect
1,000-1,100 Ohms
Are thermistor values correct ?
Inspect heat
exchanger for
blockage or damage
in the flueways.
Clean or replace as
necessary
Replace thermistor
NO
YES
NO
YES
NO
82 H......n........
(PHASE REVERSAL)
Check wiring to the boiler for
reversed live and neutral
81 H......F........
(FLAME DETECTION)
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
Summary of Contents for icos system m3080
Page 1: ......
Page 51: ...51 icos system condensing Installation and Servicing NOTES ...
Page 53: ......