Ferroli Modena 80 E Manuel D’Utilisation
MODENA 80 E
32
8. FAULT FINDING
Before beginning any fault finding ensure that gas, water and electricity are available.
WARNING: DO NOT link any terminals on block X10 or X11 as this will damage the PCB beyond repair.
8.01 Operating Sequence
With the power established the boiler is in its stand-by mode i. e. power on but no demand. The operational sequence
for C.H. and D.H.W. are as follows:
for C.H. and D.H.W. are as follows:
Central Heating Mode
External Call for Heat: The temperature regulator, built in or remote clock and room thermostat, if fitted, must all
call for heat. This will cause the pump to run.
call for heat. This will cause the pump to run.
Internal Call for Heat: C.H. flow temperature sensor, 88
°
C high limit and low water pressure switch all calling for
heat. If both external and internal calls for heat are present the MF03 PCB will energise.
In demand the fan will go to high speed causing the air pressure switch to operate. If the overheat (100
°
C) stat is
closed circuit the ignition will operate and the gas valve will be energised.
The burner will light at ignition burner pressure, automatically range rating itself up to the heating load, then
modulating down when the boiler reaches the desired flow temperature. When the central heating is satisfied the
burner will go off and the fan stops i.e. stand-by mode.
modulating down when the boiler reaches the desired flow temperature. When the central heating is satisfied the
burner will go off and the fan stops i.e. stand-by mode.
Note - If the boiler thermostat is set to maximum than the burner pressure will go to maximum effectively bypassing
the auto range rating facility
the auto range rating facility
Domestic Hot Water Mode
External Call for D.H.W: Flow meter registers at least 2.5 litres/min flow to the hot water taps.
Internal Call for D.H.W: Hot water flow temperature sensor 88
Internal Call for D.H.W: Hot water flow temperature sensor 88
°
C high limit stat and low water pressure switch calling
for heat.
If both internal and external calls are present the boiler follows the same sequence as for C.H. to light the burner.
However, for D.H.W. the burner will go straight to maximum and then modulate once the water reaches the set
temperature of the control thermostat. Turning the tap off will return the boiler to stand-by mode.
However, for D.H.W. the burner will go straight to maximum and then modulate once the water reaches the set
temperature of the control thermostat. Turning the tap off will return the boiler to stand-by mode.
Note: Following shut down of the D.H.W. or C.H. the boiler will go into a three minute central heating delay.
8.02 Limit thermostats
T/Stat
Location
Function
Nominal
Circuit
Wiring
Operating
Colours
Temperature
C.H. Limit
Top RHS
Shuts downmain
88
°
C
Low voltage
Blue
of Heat
burner if boiler
DC
Brown
Exchanger
thermostat fails
Frost
Incorporated
Fires the boiler
7
°
C - 14
°
C
Low voltage
Red
in C.H.
and runs pump to
DC
Red
Sensor
maintain minimum
water temperature
water temperature
Overheat
Top LHS
Protect boiler by
100
°
C
240V AC
Brown
of Heat
stopping ignition
Blue
Exchanger
and cuts power
to gas valve
to gas valve
The MFO3 PCB has fivediagnostic lights, each light corresponds to a particular function and will light in turn as the
boiler goes though its sequence of operations.
boiler goes though its sequence of operations.