Refrigerant charging

If the system has a boot valve the refrigerant can be supplied as a liquid to liquid line. Otherwise, the refrigerant can be supplied in the form of vapour to the compressor suction shut-off valve of the compressor from running. Charging should be continued until not vaporization is displayed in the sight glass is if the pair formation is due to other problems, see "Tips for installers, Fault localization"

If the required quantity of refrigerant is not known, use the method described above. Here, however, you need to check that the condensing pressure and suction pressure remains normal, and that the Thermostatic expansion valve overheating not too low...