3 Function description Thermo 90 S / Thermo 90 ST
302
Fig. 301 Sequence of functions
3.4 Switching off
The operating indicator on the digital timer/switch goes
out when the heater is switched off. The combustion
process will be ended and the run-on phase will start.
The circulating pump and the combustion air fan continue
to run, however, in order to cool down the heater (run-on)
and are switched off automatically after approx.
105 seconds. The heater may be switched on again
during the run-on time.
The temperature in the cabin can also be controlled using
the vehicle’s own heater fan with a cabin thermostat.
3.5 Heater functions
when installed in ADR vehicles
The heater is started using the switch. An ADR case
(constrained shut-off) is triggered when
– the vehicle’s engine is switched off,
– a pumping device is started,
in which case the short run-on is terminated after
20 seconds (Thermo 90 S) and after 40 seconds
(Thermo 90 ST).
Following this, the control unit is left in the “fault lock-out”
status. The on/off switch must be moved to “Off” before it
can be restarted.
The disconnecting switch (emergency off switch) is only
allowed to be used in case of danger, because the heater
is switched off without any run-on (overheating possible).
Sequence of functions for Thermo 90 S and ST
Switch on
Component interrogation
Pre-glow 40 s (pulsed)
Metering pump supply 5 – 7 s (1)
Metering pump / part load (1/4)
Flame monitor take-over
Stabilisation time
Full load
Vehicle fan “On”
Control range
Control pause
Flame monitor “Cold” (0)
Run-on ended
Pre-glow 15 – 20 s (pulsed)
Metering pump supply 5 – 7 s (1)
Metering pump / part load (1/4)
Flame monitor take-over
Stabilisation time
Coolant temperature reduced
Full load
Switch off (run-on)
Flame monitor “Cold” (0)
Run-on ended
A
B
C
D
E
F
G
1
0
1
0
0
0
0
0
0
1
1
1
1
1
1
/4
1
/2
1
/4
*
30 80 90 75 70 °C
23
22
212019171614131110
181512
986431
2 5 7
Safety time
❏
* If no flame is formed, the
start is automatically
repeated (20 s pulse pre-
glow, 90 s safety time).
o Possible regulating
temperatures that can be
set, see table below
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
