Volkswagen Golf Service & Repair Manual: Vapour pressure

Volkswagen Golf Service & Repair Manual / Air conditioning system with refrigerant R134a / General notes on air conditioning systems / Characteristics of refrigerant R134a / Vapour pressure

In an enclosed container that is not completely full, refrigerant evaporates as vapour at the surface in a quantity sufficient to form an equilibrium between vapour and liquid. This equilibrium develops under pressure and is often called vapour pressure. The vapour pressure is temperature-dependant → Chapter.

Physical properties of R134a

Because the vapour pressure curves of R134a and other refrigerants are in part very similar, unique identification on the basis of pressure alone is not possible.

The air conditioner compressor used for R134a is lubricated with special synthetic refrigerator oils, such as PAG oils (polyalkylene glycol oils).

Trade names and designations

Refrigerant R134a is currently available under the following trade designations: H-FKW 134a SUVA 134a ...

Effects on metal

In its pure state, refrigerant R134a is chemically stable and does not attack iron or aluminium. However, impurities such as chlorine compounds in th ...

Other materials:

Assembly overview – Brake system pressure accumulator -VX70-, RHD vehicles
1 - Brake system pressure accumulator -VX70- Removing and installing → Chapter 2 - Brake line To hydraulic unit With thread M12 x 1 14 Nm 3 -&nbs ...

Assembly overview - crankcase breather system
1 - Hose For crankcase breather 2 - Cover For oil separator 3 - Oil separator Removing and installing → Chapter Renew if damaged ...

O-ring
Use only O-rings that are resistant to refrigerant R134a and related refrigerant oils. O-rings are no longer colour-coded. Coloured and black O-rings are used. Check that the O-rings used have the correct internal diameters. ...