The a/c system is a sealed unit so if all is well will not lose refrigerant unless the parts used leak.
Havn't heared of 'ozmosis'.
You can top up a system as long as it has some charge in it and you purge the charging lines through charging to the sight glass if the car has one, or untill the suction pipe entering the compressor comes back cold with the engine revs at about 2500rpm, however this is not ideal but it does happen, believe me.
I believe a 2 year prison sentance is the maximum for an engineer venting refrigerant, at least thats what I heared. Could be wrong on that one.
I stated that the amount of refrigerant a car requires would cost a refrigeration engineer about ?5 ie. from the dumpy bottle of about 7-10kg. I didn't refer to sachet's.
Are you an engineer yourself or have you been reading a service manual.
Maybe the equipment used is of inferior quality to the rest of the trade so the dealers expect leaks, don't let them blind you with science, vehicle a/c is quite basic.
[8-|] interesting topic, well for me anyway..
Not knowing what osmosis is clearly shows you dont fully understand what your talking about, osmosis is specific to fluids. ie. for cars - water through the rubber flexihoses (which does happen) wheras the prosess is known as diffusion in more general terms, heres the definitions below, both the same thing but osmosis is specific to fluid and diffusion covers all types of particles.
All
manufacturors expect
up to 10% diffusion loss per year for systems running R134a, thats the
manufacturors not the
dealers.
Osmosis : Diffusion of fluid through a semipermeable membrane from a solution with a low solute concentration to a solution with a higher solute concentration until there is an equal concentration of fluid on both sides of the membrane.
Diffusion : the process whereby particles of liquids, gases, or solids intermingle as the result of their spontaneous movement caused by thermal agitation and in dissolved substances move from a region of higher to one of lower concentration .
Not that I want to sound derogitary but kwick fit fitters are tyre & exhaust
engineers, so I wouldnt put any more faith in a refrigeration
engineer, like you say its quite a basic system
.
I hope Im thought of as helpful on here, whether or not Im an engineer or have read a service manual. I might even write sevice manuals, who knows, but my facts are always correct before I put them up for anyone to read.
Basically you dont know the full facts on aircon.
Just found this -
http://www.airconditioningforcars.co.uk/ not the best but it goes on about molecule size affecting the long term loss or 'diffusion' and it mentions hygroscopic oil, which I spelt hydrocopic doh!
My spelling never was good.
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