Volkswagen Touran Quiz
Heating, Ventilation and Air Conditioning

Pressure and Boiling Point

In this manual: Heating, Ventilation and Air Conditioning
General Paint Information — 130Towing Guide — 4Wheel and Tire Guide Information — 111Electrical System — 104Heating, Ventilation and Air Conditioning — 106
~1min read

The boiling point given in tables for a liquid is always referenced to an atmospheric pressure of 1 bar (14.5 psi). If the pressure acting on a fluid changes, its boiling point also changes.

For example, water boils at a lower temperature the lower the pressure.

The vapor pressure curves for water and refrigerant R134a show that, at constant pressure, reducing the temperature changes vapor to liquid (in the condenser) or that reducing the pressure causes the refrigerant to change from liquid to vapor (evaporator).

Vapor pressure curve of water

A - fluid
B - Gaseous
C - Vapor pressure curve of water
1 - Pressure acting on liquid in bar (psi)
2 - Temperature in C (F)
Pressure and Boiling Point

Vapor pressure curve of refrigerant R134a

A - Fluid
B - Gaseous
D - Vapor pressure curve of refrigerant R134a
1 - Pressure acting on liquid in bar (psi)
2 - Temperature in C (F)
Pressure and Boiling Point

Test yourself

A quick Volkswagen Touran quiz: every answer comes with an explanation and a link to the manual page.