Evidence Of Leaks - Skoda Citigo 2012 Workshop Manual

Citigo 2012 ➤ , Fabia 2000 ➤ , Fabia II 2007 ➤ , Fabia II 2009 ➤ , Fab ...
Air conditioning system with refrigerant R134a - Edition 10.2014
metals and plastics being corroded. This may lead to choking,
leaks or other deposits on the AC compressor piston.
1.8.5 Behaviour with plastics
Refrigerant is a solvent for certain plastics. These dissolved plas‐
tics may be eliminated during cooling in the expansion valve. This
may result in blockage of the valve. Therefore only use original
spare parts!
1.8.6 Critical temperature/critical pressure
Up to a gas pressure of 3.95 MPa (39.5 bar) overpressure (this
corresponds to a temperature of 101°C) refrigerant R134a re‐
mains chemically stable, above this temperature the refrigerant
decomposes see ⇒ "1.8.8 Flammability", page 8
1.8.7 Water content
Water is only soluble in very small quantities in the liquid refrig‐
erant. As opposed to this refrigerant vapour and water vapour mix
in any proportion.
Water possibly present in the system is conveyed through the
refrigerant circuit as drops, once the dessicator in the fluid reser‐
voir has become saturated. The function of the dessicator is no
longer guaranteed. This water flows to the nozzle of the expan‐
sion valve where it turns to ice. This reduces the efficiency of the
cooling system.
Note
Water destroys the air conditioning system, as acids are produced
under high pressures and temperatures in combination with other
contaminations.
1.8.8 Flammability
Refrigerant is non-flammable. On the contrary it has a fire-retard‐
ant or fire extinguishing effect. Refrigerant decomposes when
brought into contact with flames or red-hot surfaces. UV light also
splits the refrigerant (generated during electrical welding). This
results in toxic fission products (hydrogen fluoride and traces of
carbonyl fluoride and fluorine), which give adequate advance
warning as they irritate the mucous membranes.
1.8.9 Filling factor
The reservoir must also include vapour space in addition to the
fluid space. As the temperature rises the fluid expands. The space
filled with vapour becomes smaller. At a given moment there will
only be fluid left in the reservoir. After this, only a minor temper‐
ature increase is required to generate very high pressures in the
reservoir as the fluid can no longer expand because there is no
more space. The resulting forces are great enough to burst the
reservoir. In order to ensure a reservoir is not over-filled, the pres‐
sure gas regulations stipulate how many kilos of refrigerant may
be filled per litre of inside volume of the reservoir. This "filling fac‐
tor" multiplied by the inside volume indicates the authorised filling
content. For the refrigerant R134a, it is 1.15°kg/l.
1.9

Evidence of leaks

The refrigerant circuit may start leaking because of external dam‐
age. Because of the small amount of leaked refrigerant, evidence
of minor leaks can be detected for example with an electronic leak
detector or leak detection additive which is filled into the refriger‐
8
Rep. gr.00 - Technical data
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