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Ferroli F 30 B
Ferroli F 30 B
MF03.1 PCB
When operating the C.H. the following lights should be on: 4, 5 and flame on light. For D.H.W. the
following lights should be on: 3, 5 and flame on light.
If the boiler works for C.H. but not D.H.W., or vice versa, a number of components must be functioning
and can, therefore, be eliminated as being at fault.
Boiler will not light for D.H.W.
If boiler works for C.H. but not for D.H.W. the fault is most likely to be the flow meter or D.H.W.
sensor.
If the tap symbol light is on the fault is the D.H.W. sensor. If this light is not on then suspect the flow
meter has not operated.
Boiler will not light for C.H.
If the boiler works for D.H.W. but not for heating the fault is most likely to be external controls (i.e.
clocks or room thermostats). Integral clock if fitted or C.H. sensor.
If the heating demand light is on the fault is most likely the C.H. sensor. If this light is not on suspect
either a clock or room thermostat not calling.
To override/eliminate any external controls disconnect them from terminal 1 and 2 on the back of the PCB cover and
refit the link wire (see fig. 22).
Boiler will not light for D.H.W. or C.H.
The fault is likely to be a component common to both services. Open a hot tap to create a demand - is
there a spark at the ignition electrode?
Yes
Suspect gas supply, pressure or gas valve.
No
Is fan running?
Yes
Suspect air pressure switch or overheat stat (if boiler locks out without sparking go to overheat stat)
No
Is low water pressure light Flashing?
Yes
Top up water to above 1 bar. Does the light stop flashing ? (if water pressure o/k suspect high limit stat)
Yes
Does fan start?
Yes
Does boiler light?
Yes
Is hot water OK?
Try heating, if heating does not work follow guide for heating faults. Does low water pressure light stop flashing
?
No
Suspect low water pressure switch.
If boiler still does not fire see comprehensive fault finding chart.
Temperature sensors (thermistors)
Identical, but individual, negative temperature co-efficient (NTC) thermistors are fitted in the C.H. and D.H.W. outlets
from the heat exchanger. As the water temperature increases the resistance in the thermistor decreases. This causes
the PCB to reduce the voltage to the modureg, in turn reducing the burner pressure. The wiring for each thermistor
is colour coded red for C.H. and blue for D.H.W.
Main printed circuit board
Secured by four plastic tabs the PCB is situated inside the control compartment. The transformer for low voltage AC
is attached to the PCB as is the DC rectifier. Potentiometers control C.H. output and maximum D.H.W. temperature,
Summary of Contents for DOMIcompact F 30 B
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