audi Workshop Repair Guides

Audi Workshop Service and Repair Manuals

ABOUT US
Incorporation of auxiliary heater into coolant circuit > < Control sequence on shutoff of auxiliary heater

A3 Mk2

Auxiliary heater temperature control curve
Auxiliary heater temperature control curve
  Note
t  Depending on the amount of heat generated by the auxiliary heater (and engine) and emitted by the heat exchangers of the air conditioning unit, the heater may remain in full-load operation, part-load operation (controlled operation) or control interval operation for a lengthy period.
t  The temperatures indicated below are approximate figures and may differ from the actual values depending on the version of the auxiliary heater.
t  If the auxiliary heater is in the control interval and receives a shut-off signal via the data bus system, it cuts out without run-on. If, however, auxiliary heater is in a different operating mode at this point, auxiliary heater control unit -J364- determines run-on required and activates the various components accordingly.
   
-A- = Power output of auxiliary heater (also as additional heater) in kW (kilowatts)
-B- = Temperature of coolant in auxiliary heater in °C (degrees Celsius)
-C- = Cut-in signal for auxiliary heater (also as additional heater) via the data bus system
-D- = Auxiliary heater starting sequence
-E- = Switchover to full-load mode
-F-= Auxiliary heater full-load mode
-G- = Activation of operating and display unit (Climatronic control unit -J255-) ON (activation is implemented in auxiliary heating mode via the data bus system)
–  Depending on version of auxiliary heater, signal for activation of operating and display unit (Climatronic control unit -J255-) is not output at 50 °C as shown, but rather at 30 °C.
-H- = Switchover from full to part-load mode
-J-= Part-load mode
-K- = Extended part-load mode
–  Only if coolant temperature exceeds 88 °C during first 6 minutes after switch-on.
-L -= Switchover to control interval
–  Auxiliary heater run-on (burn-off)
-M- = Control interval
-N- = Auxiliary heater re-start (from control interval into part-load mode)
-O- = Switchover from part to full-load mode
  A82-0505

Incorporation of auxiliary heater into coolant circuit > < Control sequence on shutoff of auxiliary heater