Abstract: Provided is a method of determining a loss of charge of refrigerant in a refrigeration system. The method comprises determining at least one performance characteristic of the refrigeration system. The at least one performance characteristic comprises a mass flow rate of the refrigerant in the refrigeration system. The method further comprises, when one or more predetermined criteria are met on the basis of the performance characteristic, determining a loss of charge in the refrigeration system.

Abstract: A method for controlling a vapor compression system, in particular an opening degree of an expansion valve. According to a first control strategy, the expansion valve is closed until the superheat value has increased above a lower threshold superheat value. According to a second control strategy, the expansion valve is kept open until the suction pressure has increased above a lower threshold suction pressure value. In the case of low superheat value as well as low suction pressure, the second control strategy is selected for a limited period of time.

Abstract: A method for controlling a vapour compression system, in particular an opening degree of an expansion valve. According to a first control strategy, the expansion valve is closed until the superheat value has increased above a lower threshold superheat value. According to a second control strategy, the expansion valve is kept open until the suction pressure has increased above a lower threshold suction pressure value. In the case of low superheat value as well as low suction pressure, the second control strategy is selected for a limited period of time.