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:
Brake support systems
First read and observe the introductory information
and safety warnings The brake support systems ESC, ABS, BAS,
TCS and EDL only function when the engine is running. They make a considerable contribution
to active driving safety.
Electronic stabilisation programme (ESC)
The ESC helps to ...
Symbols in the roof
Symbol
Meaning
Interior lights and reading lights
Electric panorama sliding/tilting glass roof
...
Contact Housings, Repairing Wire Terminals
Note
For technical reasons, the contact housing for the wire
terminals can be supplied only with the contacts pushed in.
These contacts can be removed at every other contact housing ...
© 2016-2026 Copyright www.vwpolo.net
Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information