VW Polo manuals

Volkswagen Polo Service & Repair Manual: Critical Point

Vehicle air conditioning systems make use of the vaporization and condensation process. In this case, one works with a substance which boils easily, designated as refrigerant.
The refrigerant employed is tetrafluoroethane R134a, which boils at -26.5 °C (-15.7 °F) at a vapor pressure of 1 bar (14.5 psi).
The critical point (critical temperature and critical pressure) is that above which there is no longer a boundary between liquid and gas.
A substance above its critical point is always in the gaseous state.
At temperatures below the critical point, all types of refrigerant in pressure vessels exhibit both a liquid and a gas phase, i.e. there is a layer of gas above the liquid.
As long as there is still gas present in the container next to the fluid, pressure is dependent on ambient temperature. Refer to → Chapter „Refrigerant R134a Vapor Pressure Table“.
  Note
Different types of refrigerant are never to be mixed. Only the refrigerant designated for the corresponding A/C system may be used.
   
Refrigerant R134a Physical Data
Vehicle air conditioning systems make use of the vaporization and condensation process. In this case, one works with a substance which boils easily, designated as ref ...

Refrigerant R134a Environmental Information
Vehicle air conditioning systems make use of the vaporization and condensation process. In this case, one works with a substance which boils easily, designated as ref ...

Other materials:

Vehicle identification data
Fig. 15 A: Vehicle data sticker: example shows a vehicle with engine code CCZB ③. B: Type plate Fig. 16 Vehicle identification number First read and observe the introductory information and safety warnings Vehicle identification number (FIN) The vehicle identification number can be read ...

Warning lamp
First read and observe the introductory information and safety warnings Lit up Possible cause Solution The tailgate is open or not properly closed. Do not drive on! Open the tailgate and close it again. Several warning and ...

ACC - Adaptive Cruise Control
  Note On vehicles with ACC, the trim in the right cover section of the front bumper must not be painted if paint repairs or component replacements are performed. The ACC system is located behind this section therefore a coat of paint would ...

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