Spheros thermo 231, Workshop Manual

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Igniter box
(black connector
cover) only in
combination with
control unit
1572
Igniter electrodes
2 General Description Thermo 230 / 231 / 300 / 301 / 350
204
2.8 Temperature Sensor
The temperature sensor senses the coolant temperature
at the heat exchanger outlet as an electrical resistance.
This signal is supplied to the control unit for processing.
2.9 Temperature Limiter
The temperature limiter (bimetal) protects the heater
against undue high operating temperatures.
The temperature limiter can be reset manually.
The temperature limiter responds at a temperature in
excess of 125°C to switch off the heater.
In the case of Thermo 231 and 301 as well as the Rail
variant .126, the temperature limiter will trip at a
temperature in excess of 105°C.
After the temperature has dropped, an automatic reset will
occur.
Temperature sensor
Temperature
limiter
2.10 Overheat Thermostat for burner
(Thermo 231 and 301 only)
The overheat thermostat is screwed onto the disk and
electrically connected to the solenoid valve of the fuel
pump. When the burner overheats the thermostat causes
an error lockout.
Overheat Thermostat
2.11 Circulation Pump
The externally mounted circulation pump ensures proper
coolant circulation in the vehicle and heater circuit.
Depending on the application, the circulating pump is
switched on via the control unit or directly via the vehicle
electrical system and operated during the entire heater
operation duration.
The heaters can be operated with the circulation pumps
Aquavent 5000 (U4814), Aquavent 5000S (U4854),
Aquavent 6000C (U4855) or Aquavent 6000SC (U4856).
C
irc
ul
at
in
g
pu
mp
Deli
very rate
Rat
ed vo
ltag
e
Operat
ing
volt
age ran
g
e
Rat
ed p
o
w
er con
sum
pt
ion
Weig
ht
l/h V = V = W kg
U 4814
Aquavent
5000
5000
(against 0,2 bar)
12
or
24
10…14
or
20…28
104 2,1
U 4854
Aquavent
5000S
5000
(against 0,2 bar)
24 20…28 104 2,2
U 4855
Aquavent
6000C
6000
(against 0,4 bar)
24 20…28 210 2,4
U 4856
Aquavent
6000SC
6000
(against 0,4 bar)
24 20…28 210 2,5
The circulating pump fuse may never be pulled, while the
pump is running, and may not be replaced, when the
pump is switched on.
Igniter box (green connector
cover; mechanically coded)
in combination with
control unit
1572D
and also
control
unit 1572