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:
Checking and refilling the windscreen washer fluid level
Fig. 77 In the engine compartment: cap
of washer fluid reservoir
First read and observe the introductory information
and safety warnings
The windscreen washer fluid level should be checked regularly and topped up as
necessary.
A filter can be found in the feed throat of the washer fluid re ...
Introduction
This chapter contains information on the following subjects:
→ Seat heating
Additional information and warnings:
Adjusting the seat position
Seat belts
Airbag system
Child seats (accessories)
Exterior mirrors
Luggage compartment
WARNING
Incorrec ...
Declaration of conformity
First read and observe the introductory information
and safety warningsThe individual manufacturer declares herewith that the
following products conform, at the time of vehicle production, with the basic requirements
and other relevant laws and regulations, including FCC Part 15.19, FCC Part 1 ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information