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:
Tires, Dismounting
Remove the valve insert.
Note
If equipped handle the glued-on wheel trim carefully.
Surface slightly scratched.
Replace the damaged rim wheel trim.
...
Warning lamp and coolant temperature display
Fig. 138 Coolant temperature display in
instrument cluster: Ⓐ cold; Ⓑ normal; Ⓒ warning
First read and observe the introductory information
and safety warningsA display for the coolant temperature may be, depending
on the vehicle equipment, located in instrument cluster. In normal driv ...
Introduction
This chapter contains information on the following subjects:
→ Seat covers
→ Cleaning cloth seat covers, fabric trim and Alcantara upholstery
→ Cleaning and caring for natural leather covers
→ Cleaning leatherette upholstery
→ Cleaning stowage compart ...
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