Quote:
Originally Posted by Clan
indeed , they are a bit of a bodge to say the least when you understand the proper recovery , vacuuming and recharging process ..
and when the bottle and car has reached ambient temperature how is the gas going to move from bottle to car when both pressures are the same ?
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I suppose the common auto refrigerant in Europe is R-134a, right? Our USA spec 2004 V70 and 2007 XC90 use R-134a. Personally, I no longer mess with my auto a/c units. I take it to the pro's who have the approved equipment to control discharge of freon refrigerant.
When full, the refrigerant dispensing can has a much higher pressure than the low side of a running auto a/c. There is liquid freon in the can and gaseous freon above it. So to charge into the low side without slamming liquid into the compressor one keeps the can upright.
As charging proceeds the dispensing can gets cold and the pressure inside drops. To restore pressure and speed up charging one can put the can in a container of
warm water (not hot).
In the bad old days (short on money and insufficiently concerned about the environment) I used to recharge my auto a/c's with the R-12 freon used at the time. R-12 was an efficient refrigerant and liquified at a relatively low pressure allowing a cheaper compressor. But R-12 was terrible for the stratospheric ozone layer, and I believe it is unavailable legally. In 2007 when I gave away my 1991 Dodge to someone who needed 'value' transportation, the a/c was still cold and it had never been serviced except for a adding a little R-12 every 3 or 4 years. There was a mixed hydrocarbon (no effect on stratospheric ozone) refrigerant which would work in the old R12systems, but was unapproved because it was flammable or even explosive. The only real danger I can think of would have been if there would be a full dump into the passenger compartment and it ignited before the windows could be opened.
I have a set of pressure gauges calibrated in psi and in temperatures for R-12 and R-22 so I could charge my autos with R-12 and my home a/c with R-22.
R-22 was much better for the ozone layer than R-12, but could not be used in auto a/c units because it destroyed rubber hoses. Rubber hoses were necessary to allow relative motion between the compressor on the engine and the condenser and evaporator on the body. R-22 could have been used in autos if they went to an electrically powered compressor mounted on the body, but this would have required a very high output alternator and this arrangement was not adopted (except maybe in some hybrids)
I believe R-22 is no longer manufactured in the western countries, but there are ample stores of R-22 to service older home units. My current home a/c is over 20 years old, but doesn't leak. I have a 30 lb bottle of R-22 in my garage which I will hand over for recycling when my home unit gives up.