Views: 5213 Author: Site Editor Publish Time: 2026-03-10 Origin: Site
Household water purifiers have long become a health essential for many families, and the RO membrane, as the core heart of a water purifier, directly determines the quality of purified water and user experience. Many users encounter two common problems during use — no water output from the RO membrane and a drop in desalination rate, resulting in either no pure water available for drinking or a significant reduction in filtration efficiency. Today, we will detail the troubleshooting methods, analyze the influencing factors, and share daily maintenance tips, so even beginners can easily solve these problems.
The core function of an RO membrane is to retain impurities such as heavy metals, bacteria, and salts in water. In case of any abnormality, troubleshoot in the order of from outside to inside, from easy to difficult, and most minor issues can be resolved by yourself.
In many cases, no water output is not caused by machine failure but by unmet basic conditions. First, confirm that the tap water pressure is normal (household water purifiers usually require a water pressure ≥0.1MPa; simply put, there is a steady water flow when the faucet is turned on). At the same time, check if the power supply is connected and the plug is firmly inserted to prevent the machine from failing to start water production due to power outage.
Then check the valve status: ensure the water inlet ball valve is fully open and the pressure tank (water storage tank) ball valve is in the open position. If the valves are not open or fully open, water flow cannot enter the RO membrane, and naturally, no pure water will be produced.
The RO membrane needs to work in a clean water environment, and the pre-filters (PP cotton, activated carbon) act as its protective barrier, responsible for filtering large particle impurities such as sediment, rust, and residual chlorine in water. If the pre-filters are not replaced for a long time, they will be clogged by impurities, preventing water from flowing smoothly into the RO membrane and thus causing no water output.
Troubleshooting is simple: close the pressure tank valve and open the pure water faucet. If little to no waste water flows out at this time, it can be basically judged that the pre-filters are severely clogged and need to be replaced in a timely manner.
If there is still no water output after replacing the pre-filters, it is necessary to focus on inspecting the core components:
1. High-pressure pump: If waste water flows out during machine operation but very little pure water is produced, the high-pressure pump may have insufficient pressure or be damaged. You can touch the pump outlet pipe to feel the vibration and pressure, or disconnect the RO membrane water inlet pipe to observe if the water flow is a strong water column. If the water flow is weak, the high-pressure pump is most likely faulty and needs to be repaired or replaced.
2. RO membrane itself: The RO membrane has a certain service life (usually 2-3 years). If the pre-filters are normal and the high-pressure pump is fault-free but pure water production is still very low, the RO membrane itself may be clogged or have reached the end of its service life. The signs of a clogged RO membrane are: the water production rate drops by more than 10% compared with the initial value, and the machine operating pressure rises significantly. In this case, replace the RO membrane directly.
Finally, check if the piping and accessories are normal: see if the water inlet and outlet pipes are crushed or kinked, causing poor water flow; at the same time, check for malfunctions in these small accessories:
· Water inlet solenoid valve: Malfunction may lead to water intake failure.
· Check valve (one-way valve): Malfunction may cause pure water backflow, manifested as the pressure tank being unable to store water or abnormal water output.
· Waste water proportioner: A complete blockage will also cause system pressure imbalance and no water output.
The desalination rate is the core indicator for measuring the filtration effect of an RO membrane. Simply put, it is the ability of the RO membrane to retain salts in water — the higher the desalination rate, the purer the filtered pure water. If you find that the produced water tastes salty or the conductivity increases, the desalination rate has most likely dropped, which is mainly related to the following 4 factors.
Inlet water quality directly affects the desalination effect: the higher the salt content of raw water, the greater the osmotic pressure, and the desalination rate of the RO membrane will decrease accordingly. In addition, the ionic characteristics of water also have an impact — the desalination rate of high-valence ions such as calcium and magnesium is usually higher than that of monovalent ions such as sodium and potassium. Gases such as free CO₂ and O₂ in water easily pass through the RO membrane, which will lead to an increase in the conductivity of produced water and a decrease in the desalination rate.
The operating conditions in daily use also indirectly affect the desalination rate:
· Temperature: An increase in water temperature reduces water viscosity, increasing water production, but it also accelerates the diffusion speed of salts, leading to a slight drop in desalination rate. This is a normal phenomenon and no need to worry.
· Pressure: Within a reasonable range, increasing the inlet water pressure can increase water production and dilute salts in water, thereby improving the desalination rate. However, excessively high pressure will cause membrane compaction, which will damage membrane performance and reduce the desalination rate in the long run.
· pH Value: The RO membrane has a low desalination rate under weakly acidic conditions (low pH), because hydrogen ions have a small hydration radius and easily pass through the membrane. The best desalination effect usually occurs in the pH range of 6-8.
After long-term use, the surface of the RO membrane is prone to fouling, which in turn leads to a drop in desalination rate:
· Scaling fouling: Calcium and magnesium ions in water will form scale on the membrane surface, clogging the membrane pores, which not only reduces water production but also seriously lowers the desalination rate.
· Organic/biological fouling: Organic matter in water will adsorb on the membrane surface, and microorganisms will reproduce on the membrane, changing the charge characteristics of the membrane surface, weakening the membrane's retention capacity, and making it easier for salts to pass through.
If the RO membrane sheet is scratched or the sealing ring ages, it will cause a short circuit between concentrated water and pure water, which is equivalent to unfiltered water directly mixing into pure water, resulting in a sharp drop in the desalination rate. In this case, the RO membrane or sealing ring can only be replaced.
In fact, many RO membrane malfunctions are caused by inadequate daily maintenance. Doing the following 3 points well can effectively extend the service life of the RO membrane and reduce problems such as no water output and decreased desalination rate.
1. Replace filters regularly: Strictly replace the pre-filters according to the product instructions to prevent impurities from entering the RO membrane and causing clogging and damage.
2. Rinse the RO membrane regularly: If the water purifier is not used for a long time (such as on a business trip or vacation), it is recommended to turn on the machine and run it for 5-10 minutes every week to rinse the surface of the RO membrane and prevent the deposition of pollutants.
3. Pay attention to the installation environment: Avoid installing the water purifier on a balcony exposed to direct sunlight, or in places with excessively high or low temperatures (it is easy to freeze below 0℃). Extreme temperatures will directly damage the performance of the RO membrane.