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:

Introduction
This chapter contains information on the following subjects:  → Vehicle identification data  → Engine data  → Dimensions  → Performance figures The vehicle data sticker in the service schedule or the vehicle registration documents show which engine is installed i ...

Closing the tailgate
Fig. 31 Open tailgate: handle recesses for closing the tailgate First read and observe the introductory information and safety warnings Closing the tailgate Grip one of the recesses in the interior trim of the tailgate . Pull the tailgate down with some force until it engages in th ...

Extraction and Charging System Safety Regulations
Make sure the shut-off valves are closed before connecting the charging system to the air conditioning system. Make sure the process is finished before disconnecting the charging system from the A/C system. This prevents any refrig ...

© 2016-2020 Copyright www.vwpolo.net