1. Insufficient cold water pressure: When the pressure in the cold water pipeline is insufficient, cold water will flow backwards, resulting in cascade of cold water and hot water. At this time, a one-way valve can be installed to control the return of cold water.
2. The hot water valve is not closed properly: if the hot water valve is not closed properly, there will be water leakage or water leakage, resulting in mixed flow of hot and cold water. After the hot water valve is closed tightly, this situation will be alleviated.
3. The water pipe is close to the heating pipe: some families have installed heating pipes. When the cold water pipe is close to the heating pipe, it will affect the cold water pipe, resulting in warm water flowing out of the cold water pipe. At this time, it is suggested to reinstall the water pipes and control the spacing to avoid heat transfer between pipes.
The above are several possible reasons that may lead to the series connection of cold and hot water as soon as the keys are flat. I hope I can help you. Please feel free to let me know if you have any other questions.