Carefully! If it is necessary to start the engine with an uncharged circuit: the refrigerant circuit must be completely assembled; the air conditioning compressor must contain at least a third of the amount of refrigerant provided for this circuit; The engine speed must not exceed 2000 rpm. At the same time, do not let the engine run longer than absolutely necessary, max. 10 min. Then, with an empty refrigerant circuit, the air conditioning compressor is not damaged, because. it has a safe lubrication. This means that approx. 40-50 cm3 refrigerant oil remains in the air conditioning compressor. When the refrigerant circuit is empty, the air conditioner compressor regulating valve -N280- is not actuated and the air conditioner compressor runs unloaded together with the engine. When the engine is running, the air conditioner compressor is operated by the clutch -1- and -2- (various design options) regardless of whether the air conditioner is on or off (it doesn't have an electromagnetic clutch). If the compressor is blocked, the rubber elements -2- are cut off or deformation of the driven disk -1- occurs (this can be recognized by belt pulley bulges or broken rubber in the belt pulley area).