27
FUNCTIONAL DIAGRAM
Fig. 37
NOTE: L-N-E connection is advisable
MP
Main PCB
P
1
Selector switch and heating potentiometer
P
2
DHW potentiometer
J
P
1
Calibration enable jumper
J
P
2
CH timers reset and CH max power storing when in calibration
J
P
3
Natural gas or L.P.G. selector
J
P
4
DHW thermostat mode selection (absolute)
J
P
5
Not installed
J
P
6
Not installed
L
E
D
Led 1 (green) working status or temporary stop
Led 2 (Not installed)
Led 3 (red) boiler lock out
F
1
Fuse 2A T
F
External fuse 3.15A F
M
3
Terminal strip for electrical connection hight power
P
Pump
O
P
E
Gas valve solenoids
M
O
D
Modulator
H.L.T.
Hight limit thermostat
H.T.
Heat thermistor
P.D.S
Pressure differential switch
S.S.E.
Spark /
sense electrode
T
R
X
Ignition trasformer
FF
a
n
D.H.W.F.S. Domestic hot water flow switch
D.H.W.T. Domestic hot water thermistor
W.P.S.
Water pressure switch
CN1-CN12 Connectors (CN4 Unused – CN5 bridge room thermostat (24 Vdc)