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:
Improvised Tools
Note
This list outlines the testers, tools and materials required
for expert refrigerant circuit repair work.
Caution
Non-approved tools or materials such as leak sealing
additiv ...
Introduction
This chapter contains information on the following subjects:
→ Stowage compartments in the front doors
→ Stowage compartments in the front centre console
→ Stowage compartment in the front centre armrest
→ Stowage compartment on the front passenger side
&nbs ...
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 ...
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