Technical data
Thermo 230 / 231 / 300 / 301 / 350 7 Circuit Diagrams
703
Fig. 702 Automatic Control Circuit with Control Unit 1572 and Timer (Triple Timer)
X4
7
33
51
15
62
2
6
1
2
44
3
4
3
3
2
2
1
1
4
2648
5
H3
P
H4
F1
B2
Y1
br
gr
or
gn
ϑ
ϑ
rt/ws
bl
or
br
br
sw
rt
sw
A2
X1
A
X3
D
X2
C
K2
K1
M1
M2
H2
B3
B4
S2
S3
S4
A1
B1
E1
U2
U1
SE
-
+
M
M
X4
12345678
X3
8
7
6
5
4
3
2
1
2
1
X2
X1
1
3
5
2
4
6
M1
A2
U1
A1
B1
Y1
F1/B3
E1
B2
br
br
58
75(15)
58
75(15)
F3 F6 F2
30
30
31
31
D
C
A
6
5
4
3
2
1
1
4
3
2
1 Diagnostic connector
2 to vehicle terminal +75 if available, otherwise terminal 15
3 Timer P:
with plus to connection 4 = continuous operation during immediate heating
without plus to connection 4 = heating period 1 hour
4 vehicle lighting terminal 58
Item Nomenclature Remark
A1 Heater not grounded
A2 Control unit SG 1572
B1 Flame sensor
B2 Temperature sensor
B3 Temperature limiter
B4 Thermostat opens at T > 8 °C
E1 Heating cartridge for nozzle preheating
F2 Fuse 25A flat fuse SAE J 1284
F3 Fuse 25A flat fuse SAE J 1284
F6 Fuse 5A flat fuse SAE J 1284
H3 Light in item P symbol lighting
H4 Symbol for “Heating” in Display symbol lighting (in item P)
K1 Relay (in item A2) for circulation pump
K2 Relay (in item A2) fo combustion air fan /
heating cartridge
M1 Motor combustion air fan
M2 Motor circulation pump
P Triple timing clock (1529) for timed operation
Item Nomenclature Remark
S2 Continuity switch on water cock
S3 Switch, external trigger
circulation pump
S4 Switch power save operation
U1 Igniter box
U2 Igniter electrodes
A Plug connections, 6-pole
C Plug connections, 1-pole
D Plug connections, 4-pole
X1 Plug connections, 6-pole
X2 Plug connections, 2-pole
X3 Plug connections, 8-pole
X4 Plug connections, 8-pole
Y1 Solenoid valve
bl
br
ge
gn
gr
or
rt
sw
vi
ws
Wire colors
blue
brown
yellow
green
gray
orange
red
black
violet
white
Wire gauges
< 7.5 m 7.5 - 15 m
0.75 mm
2
1.0 mm
2
1.5 mm
2
2.5 mm
2
4.0 mm
2
1.5 mm
2
1.5 mm
2
2.5 mm
2
4.0 mm
2
6.0 mm
2