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:
Recycling and Disposal Regulations
Note
The laws and regulations listed below are applicable in
Germany. Different or additional laws and regulations may apply
in other countries.
Addresses in other countries can be obtained from the
relevant au ...
Retrofitting a towing bracket
Fig. 92 Dimensions and attachment points
for retrofitting a towing bracket
First read and observe the introductory information
and safety warnings
Volkswagen recommends having the towing bracket retrofitted by a qualified workshop.
The cooling system may need to be modified or heat shields ...
Switching the front passenger front airbag on and off manually using the key-operated
switch
Fig. 58 In the stowage compartment on
the front passenger side: key switch for disabling and enabling the front airbag
on the front passenger side
First read and observe the introductory information
and safety warnings
The front passenger front airbag must be switched off when securing a
...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information