Ferroli F24 Installation, Service And User Instructions Manual page 38

8.04 Temperature sensors (thermistors)
Identical, but individual, negative temperature co-effi cient (NTC) thermistors are fi tted 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. The sensors are fi tted in wet pockets.
8.0 imit thermostats
Two surface mounted auto reset bi-metal thermostats are located on the heat exchanger secured b spring
clips. Heat sink compound is used.
8.0 ain printe ir uit oar
ecured b our 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 rectifi er. Potentiometers control C.H. output and maximum D.H.W.
temperature, both are ad ustable b the controls on the facia and because the boiler features automatic
range rating no ad ustments need to be made.
put switched live to the ignition PCB (demand rela ), the
contacts can be seen moving.
8.07 Air pressure swit h
Operating at 2 0 V AC and situated next to the fan. Different coloured tubes connect the switch to the fan. It is a
make on pressure switch and onl uses two terminals, the middle terminal is not used.
8.08 hort spares ist
.
( rom )
14 afet Valve C/W Manifold
16 Fan assembl
4 Central Heating Flow Temperature ensor
42 Domestic Hot Water Flow Temperature ensor
4 Air Pressure witch
44 Gas Valve - VK4105G
49 Overheat afet Thermostat 100°C
50 High Limit Thermostat
1 Ignition lectrode
2 Flame ensing lectrode
1 6 Flow Meter C/W lbow
Main PCB MF0
27 Heat xchanger
T
°C
lectro mechanical rela s control pump operation and
have transparent plastic covers so that their
A T . . .
05 0 9-4 5
004 0 2 - 51
00 20 2 -
00 20 2 -
00150 2 - 40
0 000 2 -76
01240 6- 15
00160 6-577
0625 26- 4
014 2 - 55
05910 9-465
05900 9-470
074 0 77-470
.
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