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:
Wear Spots
Wear spots are caused by a hard stop with locked wheels
whereby the rubber compound is abraded from the contact patch.
When the tires slide across the road surface, frictional
heat is generated which reduces the abrasion resistance on the
...
Battery Terminal Clamp and Battery Terminal, Cleaning
Special tools and workshop equipment
required
Torque Wrench 1331 5-50Nm -VAG1331-
The Contact Surface Cleaning Set -VAS6410- makes optimal
repair quality possible in the realm of vehicle electronics.
Using th ...
Washing the vehicle with a high-pressure cleaner
First read and observe the introductory information
and safety warningsFollow the instructions provided by the manufacturer when
cleaning your vehicle using a high-pressure cleaner. This applies in particular
to the pressure and the spraying distance .
Maintain sufficient distance to soft m ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information