Checking heat output of air conditioner and operation of pump valve unit — AUDI

Audi
Audi A6
2005
Heating, ventilation, air conditioning system
Air conditioning
Edition
02.2008
Checking heat output of air conditioner and operation of pump valve unit
If the coolant circuit is not completely bled after filling, air may accumulate in the heat exchangers of the air conditioner unit and thus reduce the heat output. In addition, noise may occur or complaints may be received about differences in the temperature of the air from the driver's and front passenger's vents despite identical setting
Engine, mechanics
Rep. Gr.
19
.
In the event of complaints about blubbering noise from the heat exchanger of the air conditioner unit or poor air conditioner heat output under certain ambient conditions (a
coolant circulation pump
V50
fault may also have been stored), check the incorporation of the pump valve unit into the coolant circuit. If air bubbles are visible in the upper connection of the coolant expansion tank with the engine running, additionally check for the correct version of the coolant expansion tank
Engine, mechanics
Rep. Gr.
19
and
Electronic parts catalogue
.
Remedy:
On operating and display unit,
Climatronic control unit
J255
set air conditioner to max. heat output for driver's and front passenger's side (
“Hi”
temperature setting or both rotary temperature controls on right stop).
Perform lengthy test drive at high engine speed (at least 10 minutes, engine speed above 2500 rpm). In doing so, select low gear to prevent excessive vehicle speed.
In the event of complaints about poor heat output at certain engine speeds, check incorporation of pump valve unit into coolant circuit. If both coolant hoses (supply and return) from the engine to the pump valve unit or the electrical connections in the connector to the
coolant circulation pump
V50
have been interchanged, the engine coolant pump works in opposition to the pump in the pump valve unit and there will be no flow of coolant into the heat exchanger at certain engine speeds
Engine, mechanics
Rep. Gr.
19
and
Current flow diagrams, Electrical fault finding and Fitting locations