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:

Tires, Dismounting
Remove the valve insert.   Note If equipped handle the glued-on wheel trim carefully. Surface slightly scratched. Replace the damaged rim wheel trim.     ...

Warning lamp and coolant temperature display
Fig. 138 Coolant temperature display in instrument cluster: Ⓐ cold; Ⓑ normal; Ⓒ warning First read and observe the introductory information and safety warningsA display for the coolant temperature may be, depending on the vehicle equipment, located in instrument cluster. In normal driv ...

Introduction
This chapter contains information on the following subjects:  → Seat covers  → Cleaning cloth seat covers, fabric trim and Alcantara upholstery  → Cleaning and caring for natural leather covers  → Cleaning leatherette upholstery  → Cleaning stowage compart ...

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