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:

Test Requirements
Radiator and condenser are clean (clean if necessary). The ribbed belt for the A/C compressor and alternator tensioned correctly. All air ducts, covers and seals are OK and installed correctly. ...

Changing bulbs in the front headlights (halogen H4)
Fig. 178 Rear view of the right-hand H4 headlight with plastic covers: ① dipped beam and main beam, ② turn signal and ③ side light Fig. 179 Rear view of the right-hand H4 headlight with rubber cover: ① dipped beam and main beam, ② turn signal and ③ side light First read and o ...

Battery Safety Label
Battery Safety Label 1. -  When working in the area of batteries, fire, sparks, open flame and smoking are prohibited. Avoid sparks when working with cables and electrical devices, and from electrostatic discharge. Avoid s ...

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