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. |
|
|
|
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:
Introduction
This chapter contains information on the following subjects:
→ Vehicle identification data
→ Engine data
→ Dimensions
→ Performance figures
The vehicle data sticker in the service schedule or the vehicle registration
documents show which engine is installed i ...
Closing the tailgate
Fig. 31 Open tailgate: handle recesses
for closing the tailgate
First read and observe the introductory information
and safety warnings
Closing the tailgate
Grip one of the recesses in the interior trim of the tailgate .
Pull the tailgate down with some force until it engages in th ...
Extraction and Charging System Safety Regulations
Make sure the shut-off valves are closed before connecting
the charging system to the air conditioning system.
Make sure the process is finished before disconnecting the
charging system from the A/C system. This prevents any
refrig ...
© 2016-2020 Copyright www.vwpolo.net
Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information