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:
Smooth Tube, Repairing
A new repair concept has been developed for repairing washer
system hoses. Various individual hose connectors, adapters,
Ethylene Propylene Diene Methylene (EPDM) rubber hoses and
shrink tubing will be offered as replacement parts.
Smoot ...
4-Pin Heated Oxygen Sensor (HO2S), Removing and Installing
Note
Do not repair the heated oxygen sensor wires. Repairing may
result in malfunctions.
Use the faulty sensor as a guide for installing all of the
accompanying attachments, cable ties or marking bands.
...
Technical Requirements
The wheel and tire combinations or retrofittings listed in
the individual vehicle tables refer exclusively to original disc
wheels.
Release of wheel/tire combinations or retrofittings with
disc wheels from the accessories trade is ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information