UNIPRODO UNI_WS_5000PLUS Manual De Instrucciones página 39

The frequency of filter replacement varies depending on the quality of the water
supply. However, refer to the filter cartridge usage statistics.
The recommended frequency is every 6 months.
Signs indicating that the filter needs to be replaced:
a) deterioration of treated water quality,
b) restricted water supply,
c) regeneration cycle has no effect.
3.1. How to replace the cartridge:
1. Remove the 4 screws on the back of the unit.
2. Lift the cover.