1. Keep the main valve for water intake and drainage and all branch valves closed.
2. Unscrew the plug of the backwater section with a wrench. (There may be a little water overflow during the unscrewing process. You can put a towel under it during the unscrewing process. )
3. Cut a rectangular hole above the back end of a large plastic bottle with scissors, and put the rectangular hole end of the bottle under the screw plug that has just been unscrewed.
4. Open the valve of one of the components.
5. Slowly loosen the main inlet valve (red frame) and keep the main return valve (green frame) closed. At this time, the plastic bottle stopper will discharge sewage.
6. Until the sewage connected to the plastic bottle becomes clean water, the floor heating pipes of this road are cleaned, and other branch pipes can be closed and opened in turn for sewage discharge.
7. After all branches are cleaned, screw back the plug and open the main water inlet valve and main water return valve.
8. Open all diverter valves and you can use the floor heating normally.