GF83.70-P-3048A | Increase in coolant temperature during partial load operation, function | 3.4.98 |
MODEL 210 from 1.3.97 to 31.5.98 with ENGINE 602.982
with heater booster
P83.70-0409-09
1 Burner housing
2 Heat exchanger
A1 Instrument cluster
M13 Coolant circulation pump
Y23 Fuel metering pump
A6m2 Combustion air blower
A6n1 Heater booster control module
G2 Generator
Function sequence
The temperatures for switching thresholds have been changed as of 1 February 98. The temperature values indicated in parentheses are valid up to 31 January 98.
1 Coolant temperature > 64 °C and < 76,5 °C
(> 61 °C and < 72 °C)
Outdoor air temperature 5 °C
The vehicle engine runs and the instrument cluster (A1) is actuated by the generator (G2) via circuit 61 (charge indicator). The heater booster control module (A6n1) receives a positive signal for operation of the heater booster from the instrument cluster (A1).
2 The heater operates at partial load. The combustion air blower (A6m2) and fuel metering pump (Y23) operate at partial load speed and output. The coolant circulation pump (M13) pumps coolant through the heat exchanger (2).
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3 In spite of the fact that the heater is operating at partial load the coolant temperature continues to increase due to the slight heat requirement.
4 The coolant temperature reaches 76.5 °C (72 °C).
5 The control module (A6n1) shuts off the heater booster.
6 The fuel metering pump is switched off and the combustion in the burner housing (1) interrupted.
7 The heater shut-off delay starts for approx. 110 s to cool down the heater and purge the combustion chamber.
8 After completion of the heater shut-off delay the combustion air blower is switched off.
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9 Operation of the heater booster is terminated.
10 The coolant circulation pump (M13) continues to pump coolant through the heat exchanger (2) although the heater is switched off.
The heater booster is started up again when the temperature of the coolant drops below 68 °C (60 °C) as a result of a decrease in the outdoor air temperature and/or frequent operating pauses, etc.