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 ...
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 ...
Evacuating and Charging Valve, Low Pressure Side
Special tools and workshop equipment
required
Torque Wrench 1783 - 2-10Nm -VAG1783- with Torque Wrench
1783 - 1/4" Drive Ratchet -VAS6234-
WARNING
There is a dan ...
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