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. |
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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:
Reservoir
Caution
Non-approved tools or materials such as leak sealing
additives can cause damage or malfunctions in the
system.
Only use tools and materials approved by the
manufactu ...
Warning lamp
Fig. 44 Warning lamp in the instrument
cluster
First read and observe the introductory information
and safety warnings
Lights up or flashes
Possible cause
Solution
The driver seat belt and, if the front passenger seat
is occupied, the fr ...
Support Mode with Battery Charger -VAS5095A
General Information
The support mode provides the vehicle electrical system with
voltage when the battery is removed or disconnected.
For more information. Refer to Battery Charger -VAS5095A-
Operating Instructions.
...
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