What do you do if the display of the A/C service unit reads “Bad refrigerant!” after having done the refrigerant analysis? This display message means that the refrigerant contained in the system is not OK, i.e. contaminated with other gases.
In such a case you must not simply recover the refrigerant, but use the disposal port of the A/C service unit to drain the refrigerant into a container specially designed for the purpose.
A safe method to recover contaminated refrigerant is to let it condense into a recycling bottle by means of dry ice at a temperature of about –80°C. This method has two benefits. First, there’s no need for a suction pump. Second, cooling down the gas significantly reduces the reactivity of harmful substances.