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:
Dimensions
Fig. 17 Dimensions
First read and observe the introductory information
and safety warnings
The data in the table apply to the most basic German model.
The specified values can vary due to different tyre and wheel sizes, if additional
equipment is fitted, for different model versions, for ret ...
Introduction
This chapter contains information on the following subjects:
→ Opening or closing the windows electrically
→ Electric windows – functions
→ Roll-back function for the electric windows
Additional information and warnings:
Central locking system
Cleaning and ...
Parking Aid Sensor, Painting
The following parameters must be met when painting to avoid
malfunctions in the parking aid sensor (parking aid system):
New Part, Painting
Maximum coat thickness 125 µm; the coat thickness must
always be measured ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information