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:
“2 Color” Visual Indicator, Checking
WARNING
Risk of injury. Follow all Warnings and Safety
Precautions. Refer to
→ Chapter „Warnings and Safety Precautions“.
Visual Indicator General Informatio ...
Checklist
To ensure your own safety and that of your passengers, observe
the following actions in the specified order :
Stop the vehicle at a safe distance
away from moving traffic and on a suitable surface .
Switch on the hazard warning lights
using the button .
Apply the handbrake ...
Description and function of the airbags
First read and observe the introductory information
and safety warnings
The airbags can protect vehicle occupants during frontal and side collisions
by reducing their movement in the direction of the collision.
When an airbag is triggered, it is inflated by a gas generator. This causes the
...
© 2016-2026 Copyright www.vwpolo.net
Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information