Capillary size design of R-134a system while retrofitting R12 system?
The capillary tube is usually 10-20 % longer for R-134a systems. d. Recovery & Recycling Q1 Can we use a common Recovery machine for both CFC & HFC systems? A common recovery machine can be used, if every time, a change in refrigerant handling is encountered, the machine is evacuated and all traces of the earlier handled refrigerant is removed. A vacuum of at least 1000 microns is needed for this. However, as such disciplined procedures are seldom practiced in the field, it is safer to use separate Recovery machines for each of the refrigerants. Separate Recovery cylinders are to be used for each refrigerant. It should be remembered that R12 & 134a form a high pressure azeotrope in all proportions and a contamination exceeding 2 to 3% is bad. Q2 Any simple test to identify the acidity in lubricants? The simplest test is to use a litmus paper that turns from blue to red. This only tells you of the presence of acid but not whether it is at an acceptable level or not. A better test is the
