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:
Accessories and parts
First read and observe the introductory information
and safety warningsVolkswagen recommends that you seek advice from a Volkswagen
dealership before purchasing accessories, spare parts or service fluids. For example,
if the vehicle is to be retrofitted with accessories or if parts have to be ...
Windshield and Rear Window Washer System
The following hose connection types are used for connecting
hoses to pumps and spray nozzles or as separating points
–
To loosen the connection, pulling both halves of the
coupling apart.
...
Introduction
This chapter contains information on the following subjects:
→ Warning and indicator lamp
→ Pedals
→ Manual gearbox: selecting a gear
→ Automatic gearbox: selecting a gear
→ Changing gear using Tiptronic
→ Driving with an ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information