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. |
|
|
|
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 ...
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:
→ Ignition lock
→ Starting the engine
→ Stopping the engine
→ Electronic immobilizer
Notes in this chapter concerning the automatic gearbox are applicable
both for the automatic gearbo ...
Waxing and polishing the vehicle
First read and observe the introductory information
and safety warningsWaxing
Waxing protects the paintwork. You will need to re-wax the vehicle with a good
hard wax if water no longer clearly forms small drops
and runs off the paintwork when it is clean.
Even if a wax solution is used regul ...
Electrically Driven A/C Compressor, Flushing
Vehicles with a high voltage system
Observe all of the additional warnings for all work
performed on vehicles with the high voltage system. Refer to
→ Electrical Equipment; Rep. Gr.93.
...
© 2016-2025 Copyright www.vwpolo.net
Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information