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:
6-Pin Universal Oxygen Sensor, Removing and Installing
Note
Use the faulty sensor as a guide for installing all of the
accompanying attachments, cable ties or marking bands.
Do not crimp or cut the wires otherwise the functionality of
the heated oxygen sensor (HO2S) will ...
Electric panorama sliding/tilting glass roof – function
First read and observe the introductory information
and safety warnings
Convenience opening and closing
The electric panorama sliding/tilting glass roof can be opened and closed from
the outside with the vehicle key.
Press and hold the locking or unlocking button on the vehicle key. The e ...
Battery Charger -VAS5095A- Maintenance Charging
WARNING
Risk of injury. Follow all Warnings and Safety
Precautions. Refer to
→ Chapter „Warnings and Safety Precautions“.
WARNING ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information