Turn off the power supply and shut the main water inlet valve to the purifier.
Remove and replace the Sediment Filter (the first line of defense against dirt and rust).
Replace the internal filters, typically the Pre-Carbon Filter (removes chlorine and odor) and the Sediment Filter (if it has a second internal one).
Replace the Post-Carbon Filter (which polishes the water’s taste before it reaches the tap).
Meticulously check all connections, joints, and new filter housings for any leaks. This is a step you don’t want to rush.
Check the water flow rate from the tap and ensure the auto-shutoff mechanism is working.