Laundry treatment apparatus (2, 70) being a laundry dryer, a washing machine or a washing machine having drying function, the apparatus having a heat pump system, the heat pump system having a refrigerant loop comprising: a treatment chamber for treating laundry using a medium, a first heat exchanger for heating a refrigerant, a second heat exchanger for cooling the refrigerant and heating the medium, a refrigerant expansion device arranged in the refrigerant loop between the second heat exchanger and the first heat exchanger, a compressor arranged in the refrigerant loop between the first heat exchanger and the second heat exchanger characterized in that said apparatus further comprises a safety unit (32; 34, 34a, 44, 38, 42, 55; 80, 84) comprising or being a refrigerant condition detector (34, 44, 38, 42, 55; 80, 84) arranged at or in fluid connection to the refrigerant loop, wherein the safety unit is configured to detect an overpressure state in the refrigerant loop, wherein the refrigerant condition detector (34, 34a, 44, 38, 42, 55; 80, 84) is adapted to provide a detector signal and/or a switching signal, or is operating as switch (80, 84), wherein in dependency of the refrigerant condition indicated by the detector signal or switch (80, 84) an operating mode of the heat pump system is modified by one or more of the following: A) the operation mode of the apparatus (2, 70) is modified, by one of the following: switching off the power supply to the apparatus, setting the apparatus to a standby mode until the state of the detector signal or switch (80, 84) is changed, setting the apparatus to a standby mode for at least a period of time, or changing to a secured operation mode, B) the operation mode of the compressor is modified by one of the following: switching off the power supply to the compressor, for at least a period of time, setting the compressor to a standby mode until the state of the detector signal or switch is changed, setting the compressor to a standby mode for at least a period of time, or switching the compressor on and off intermittently and/or increasing the off/on operation periods for the compressor, and C) the operation mode of an air blower (17, 19) is modified. a treatment chamber for treating laundry using a medium, a first heat exchanger for heating a refrigerant, a second heat exchanger for cooling the refrigerant and heating the medium, a refrigerant expansion device arranged in the refrigerant loop between the second heat exchanger and the first heat exchanger, a compressor arranged in the refrigerant loop between the first heat exchanger and the second heat exchanger characterized in that said apparatus further comprises a safety unit (32; 34, 34a, 44, 38, 42, 55; 80, 84) comprising or being a refrigerant condition detector (34, 44, 38, 42, 55; 80, 84) arranged at or in fluid connection to the refrigerant loop, wherein the safety unit is configured to detect an overpressure state in the refrigerant loop, A) the operation mode of the apparatus (2, 70) is modified, by one of the following: switching off the power supply to the apparatus, setting the apparatus to a standby mode until the state of the detector signal or switch (80, 84) is changed, setting the apparatus to a standby mode for at least a period of time, or changing to a secured operation mode, switching off the power supply to the apparatus, setting the apparatus to a standby mode until the state of the detector signal or switch (80, 84) is changed, setting the apparatus to a standby mode for at least a period of time, or changing to a secured operation mode, B) the operation mode of the compressor is modified by one of the following: switching off the power supply to the compressor, for at least a period of time, setting the compressor to a standby mode until the state of the detector signal or switch is changed, setting the compressor to a standby mode for at least a period of time, or switching the compressor on and off intermittently and/or increasing the off/on operation periods for the compressor, and switching off the power supply to the compressor, for at least a period of time, setting the compressor to a standby mode until the state of the detector signal or switch is changed, setting the compressor to a standby mode for at least a period of time, or switching the compressor on and off intermittently and/or increasing the off/on operation periods for the compressor, and C) the operation mode of an air blower (17, 19) is modified.