How to recharge oil in R-134a system?
The oil should not be exposed to the atmosphere and the best way of charging oil is by fitting a hand operated pump directly on the mouth of the oil can and connecting its outlet through a hose to the compressor’s process tube whereby everything is a closed circuit without exposure to the atmosphere. Alternatively, after evacuation and leak testing, the oil from the sealed tin can be drawn in by the vacuum into the compressor.
