Roborock S8 Pro Ultra (S81USP) reduced mop washing performance
Cause 1 of 2The mop is not attached properly. Source: Common Issues, p. 15
First checkReinstall the mop.
Causes and checks
The mop is not attached properly. Source: Common Issues, p. 15
- Reinstall the mop.
The floor is dirty. Source: Common Issues, p. 15
- Change the mop washing mode to "Deep" in the app.
All 2 causes checked. Contact the manufacturer.
Other S8 Pro Ultra (S81USP) problems
- The robot will not power on2 causes in the manual. First: the battery level is low.
- The robot will not charge2 causes in the manual. First: the dock may not be receiving power.
- The robot charges slowly2 causes in the manual. First: the robot automatically reduces its charging speed at high or low temperatures to extend battery life.
- The robot cannot dock2 causes in the manual. First: there are too many obstacles near the charging dock.
- The robot behaves abnormallyThe robot behaves abnormally without showing an error.
- The robot is noisy during cleaning2 causes in the manual. First: the main brushes, side brush, main wheels or omnidirectional wheel may be jammed.
- The robot cannot connect to WiFi5 causes in the manual. First: wiFi is disabled.
- Poor cleaning ability or dust falling out3 causes in the manual. First: the dustbin is full.
- Scheduled cleaning is not workingThe battery level is low; scheduled cleaning can only begin when the battery level is above 20%.
- No or little water during moppingThe water tank may be empty, or the scrub intensity or the mop installation needs checking.
- Cleaning does not resume after recharging2 causes in the manual. First: the robot is in DND mode, which prevents cleanup.
- The robot cannot return to the dock after spot cleaning or being movedAfter spot cleaning or a significant position change the robot regenerates the map; if the dock is too far away it may not return to recharge.
- The robot misses certain spotsThe wall sensor or cliff sensors may be dirty.
- Reduced emptying performance or unusual noise when emptying2 causes in the manual. First: the main brushes or main brush cover are not properly installed.
- Auto-emptying is not working4 causes in the manual. First: auto-emptying is disabled.
- The mop is not washed4 causes in the manual. First: the mop is not used, so it is not washed.
- Poor drying effect3 causes in the manual. First: auto Drying is disabled in the app.
Sources
- Roborock S8 Pro Ultra FCC EN User Manual (EN/FR/ES). Beijing Roborock Technology Co., Ltd. Document S81USP, revision Undated download (PDF created 2023-03-14), 15 pages, en. support.roborock.com. Listed on the manufacturer's support page. Retrieved 13 November 2026.
- What should I do when error 4 occurs?. Beijing Roborock Technology Co., Ltd. Document Article 360035369132, revision Undated web article, 1 pages, en. support.roborock.com. Listed on the manufacturer's support page. Retrieved 13 November 2026.
- What should I do when error 5 occurs?. Beijing Roborock Technology Co., Ltd. Document Article 360035369172, revision Undated web article, 1 pages, en. support.roborock.com. Listed on the manufacturer's support page. Retrieved 13 November 2026.
- What should I do when error 7 occurs?. Beijing Roborock Technology Co., Ltd. Document Article 360035369212, revision Undated web article, 1 pages, en. support.roborock.com. Listed on the manufacturer's support page. Retrieved 13 November 2026.
- What should I do when error 9 occurs?. Beijing Roborock Technology Co., Ltd. Document Article 360035731551, revision Undated web article, 1 pages, en. support.roborock.com. Listed on the manufacturer's support page. Retrieved 13 November 2026.
- What should I do when error 10 occurs?. Beijing Roborock Technology Co., Ltd. Document Article 360035731571, revision Undated web article, 1 pages, en. support.roborock.com. Listed on the manufacturer's support page. Retrieved 13 November 2026.
- What should I do when error 13 occurs?. Beijing Roborock Technology Co., Ltd. Document Article 360035369312, revision Undated web article, 1 pages, en. support.roborock.com. Listed on the manufacturer's support page. Retrieved 13 November 2026.
- What should I do when error 18 occurs?. Beijing Roborock Technology Co., Ltd. Document Article 360035731631, revision Undated web article, 1 pages, en. support.roborock.com. Listed on the manufacturer's support page. Retrieved 13 November 2026.
Page numbers are the numbers printed in the manual. Where this page and the manual differ, follow the manual.