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:
Overview - Wheel, Standard
1 -
Wheel
Installing the wheel. Refer to
→ Chapter „Wheel, Mounting“.
2 -
Wheel Bolts
There are different versions. Refer to
→ Chapter „Wheel Bolts“.
3 -&nb ...
Introduction
This chapter contains information on the following subjects:
→ Indicator lamps
→ Turn signal and main beam lever
→ Switching lights on and off
→ Lights and vision – functions
→ Masking or switching over headlights for driving abroad (travel mode)
...
Evacuating and Charging Valve, High 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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