27
FUNCTIONAL DIAGRAM
Fig. 41
NOTE: L-N-E connection is advisable
AKL
Main PCB
P1
Selector switch and heating potentiometer
P2
DHW potentiometer
P3
Unused
P4
Unused
JP1
Unused
JP2
Unused
JP3
Unused
JP4
Unused
JP5
Unused
JP6
Unused
JP7
Unused
JP8
Closed -
Unused
LED
Led 1 (green) working status or temporary stop
Led 2 (yellow) CO2 function ON
Led 3 (red) boiler lock out
CN1-CN15
Connectors - CN5 Room thermostat (24 Vdc)
S.W
.
CO2 function button
F.S. (1)
Flame sensor
F1
Fuse 3.15A
T
F
External fuse 3.15A
F
M3
Terminal strip for electrical connection hight power
P
Pump
OPE
Gas valve solenoids
F Hv
Fan power supply 230 V
F Lv
Fan signal control
D.H.W
.F
.S
Domestic hot water flow switch
D.H.W
.T
Domestic hot water temperature
WPS
W
ater pressure switch
S.E.
Spark electrode
TSC2
Ignition transformer
3W
3 way motor
F.O.H.T
Flow over heat thermostat
FS
Flue sensor
FT
Flow thermistor (NTC)
RS
Return thermistor (NTC)