Thermo Pro 90 3 Description of Operation
301
3 Description of Operation
3.1 Switching on and residual-heat utilisation phase
The heater is switched on depending on the equipment
variant by means of a switch or standard timer.
Activating residual-heat utilisation phase
The coolant temperature is checked by the heater each time
the heater is switched on, before the heating process. If the
coolant temperature is above 60 °C, the residual-heat
utilisation phase is activated automatically. When the
residual-heat utilisation phase is active, the circulation pump
of the heater and the vehicle fan are controlled
automatically.
The activation of the residual-heat utilisation phase can only
take place from the “OFF” state, i.e. in the “residual-heat
utilisation phase“ state, there is no transition from the states
"Fault lock-out", "ADR lock-out" and "Heater lock-out".
Deactivating residual-heat utilisation phase
The residual-heat utilisation phase is deactivated:
a) when the lower limit of the operating voltage is reached
b) when the coolant outlet temperature is below 40 °C
c) when the heater is switched off.
If the criteria a) or c) are met when activating the residual-
heat utilisation phase or during the residual-heat utilisation
phase, then there is a transition to the “OFF" state.
Fig. 301 Operating sequence of Thermo Pro 90
Glow plug
Metering pump
Combustion air
fan
Exhaust
temperature
sensor
Operating
indicator lamp
Circulation pump
Vehicle fan
1) Switching on
2) Component check
3) Preheating 40 s.
4) Metering pump/partial load (1/4)
5) "Flame ON" detection
6) Stabilisation time
7) Full load
8) Vehicle fan "On"
9) Control range
10) Control break
11) "Flame OFF” detection
12) Run-on ended
13) Preheating 15 to 20 sec.
14) Metering pump/partial load (1/4)
15) "Flame ON" detection
16) Stabilisation time
17) Coolant temperature dropped
18) Full load
19) Switching off (run-on)
20) "Flame OFF” detection
21) Run-on ended
Possible encodable control temperatures
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