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:
A/C Compressor Regulator Valve -N280
Note
For switching pressures, removing and installing switches
and switch arrangement and version, see vehicle-specific
refrigerant circuit.
Refer to
→ Rep. Gr.87.
...
Lifting the vehicle with the jack
Fig. 168 Jacking points for the
vehicle jack (mirrored on the right-hand side of the vehicle)
Fig. 169 Vehicle jack at the rear
left-hand side of the vehicle
First read and observe the introductory
information and safety warnings
The jack may be applied only at the jacking points shown (m ...
Fender Corrosion Repair Measures, in Wheel Housing Liner Contact Area
Note
The corrosion protection in the fender seam must be applied on all
replacement parts, on which the attached seal is not already present.
The additional corrosion protection seal will prevent “chafe marks”
in the fender wheel housing liner.
...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information