If the refrigerant is contaminated or contains moisture, this may damage the compressor and other components. The carefully produced MAHLE filter-driers, which - depending on the system - are also called accumulators, prevent this: the liquid refrigerant flows through this component and passes through a hygroscopic filter, which retains both moisture and fine particles. However, as the filter-drier can only absorb a limited amount of moisture before the drying medium becomes saturated, it must be replaced regularly - every two years or every time the refrigerant circuit is opened. Filter-driers from MAHLE also fulfill another important task: their top section serves as a compensation chamber, while the lower section acts as a refrigerant store. This compensates pressure fluctuations in the system in an optimal way.