Audi Workshop Service and Repair Manuals > A4 Mk3 > Heating, ventilation, air conditioning system | Auxiliary heater | Aux. heater/heater booster | Functional description of auxiliary heater | Sequence with required heat output less than 50 %

Sequence with required heat output less than 50 %

P (kW) = Heat output in kilowatts

t (°C) = Temperature of coolant in heater (in degrees centigrade)

A = Commencement of starting (coolant temperature in heater must be less than 60 °C).

B = Starting

C = Full load operation

D = Part load operation

E = Control interval

F = Starting from control interval.

1 = Start of full load operation.

2 = Switchover from full to part load operation.

3 = Switchover from part load operation to control interval.

4 = End of control interval.

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