Pressure Relief Valve
WARNING: This page is about a different car, the 2018 Nissan NV3500 HD, 2018 Nissan NV2500 HD, and 2018 Nissan NV1500. However, it is still accessible from the selected car via links, so may be relevant.
The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor. When the pressure of refrigerant in the system increases to an abnormal level [more than 2, 990 kPa (30.5 kg/cm 2 , 433.6 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into the atmosphere.