Water purifier and control method therefor

A water purifier comprising:

• a raw water flow path along which raw is flowable;
• a purified water flow path connectable to the raw water flow path and, with the purified water flow path connected to the raw water flow path, along which the raw water from the raw water flow path is flowable;
• at least one filter provided in the purified water flow path and configured to filter the raw water that is flowable along the purified water flow path and to discharge purified water to the purified water flow path downstream of the at least one filter;
• a washing water flow path connectable to:
• the raw water flow path and, with the washing water flow path connected to the raw water flow path, along which the raw water from the raw water flow path is flowable, or
• the purified water flow path and,
• with the washing water flow path connected to the purified water flow path,
• along which the raw water from the purified water flow path is flowable, or
• along which the purified water from the purified water flow path is flowable;
• a washing water generator in the washing water flow path and configured to electrolyze the raw water or the purified water that is flowable along the washing water flow path to generate washing water including hypochlorous acid and to discharge the generated washing water to the washing water flow path;
• a valve in at least one of the raw water flow path, the purified water flow path, and the washing water flow path;
• an optical sensor at a discharging end of the washing water generator, the optical sensor configured to sense a degree of generation of bubbles included in the generated washing water and output a value corresponding to the sensed degree of generation of bubbles;
• and
• a controller configured to:
• selectively connect the raw water flow path to the washing water flow path or the purified water flow path based on a washing operation,
• control the washing water generator and the valve to perform the washing operation, and
• identify whether an error has occurred in the washing operation based on the value output from the optical sensor.