The situation when a smart cleaning assistant suddenly stops washing the floor and issues a voice alert or notification in the app that there is not enough water, is familiar to many owners of Xiaomi, Roborock and Viomi equipment. Often this happens at the most inopportune moment, interrupting the planned cleaning, although the user is sure that the tank is flooded to the brim. This behavior of the device can be caused by a banal clog, and a software failure or malfunction of the hardware of the fluid supply system.
Understanding the electronic pump and level sensors allows you to quickly diagnose the problem without going to the service center. In most cases, the water supply error is associated with oxidation of contacts, the formation of an air plug in the tubes or the accumulation of lime plaque on the filter. Below we will discuss in detail the algorithm of actions that will help return your gadget to the ability to wet cleaning.
Checking the integrity of the tank and correct installation
The first step should always be to test the mechanical part, make sure the water tank is placed in the slots before the characteristic click. If the module is inserted loosely, the contact groups may not close, and the robot motherboard simply won't see the tank, giving a fluid shortage error, and also check if the tank is upside down or side-shifted.
Carefully inspect the tank itself for cracks or chips. Even microscopic damage to the housing can lead to depressurization of the system and a drop in pressure, which is perceived by the electronics as lack of water. Pay special attention to the mounting areas of the pump and the exit hole.
Sometimes the problem is the tank lid, if it's not fully closed, or if the rubber seal is shifted, air enters the system, disrupting the vacuum pump, and make sure that the rubber plug on the filler hole fits tightly and has no deformations.
Critically, if you use non-original tanks or third-party tanks, the error may be due to mismatching the geometry of the contacts or the lack of magnets that some robot models use to identify the capacity.
- 💧 Check the density of the tank to the body of the robot.
- 🔍 Inspect the tank for microcracks and chips.
- 🔒 Make sure the cover and plugs are sealed.
- 🧲 Check the presence and position of the magnets (if applicable).
⚠️ Warning: Never attempt to operate a robot vacuum cleaner with a cracked tank. Getting water inside the device case is guaranteed to short the main board and costly repairs.
Removal of air traffic jams in the supply system
One of the most common reasons Xiaomi Robot Vacuum writes that water is scarce is to suffocate the system. The air plug blocks the flow of fluid from the tank to the pump and then to the carpet nozzle, which often happens if the tank is empty for a long time or filled with too hot water, which, when cooled, created a rarity.
To eliminate this problem, you need to create a pressure that will push the air out, take a syringe (preferably without a needle) or a pear to clean, hold the spout of the syringe to the outlet of the tank (below or behind where the valve is) and try to gently draw the water in, creating a vacuum, and then squeeze it back sharply. Repeat the procedure several times.
And the blowing method also helps. Take the tank off, flip it over, and lightly tap on the bottom of the valve where the valve is located to make the air bubbles float, then press the valve with your finger to let the air out, and pour the water again, sometimes it takes several cycles of filling and draining to fully normalize the work.
Can I use a syringe with water?
- 💨 Use a syringe to create pressure in the valve.
- 🔄 Make several cycles of dialing and draining water.
- 👇 Easily tap on the bubble tank.
Cleaning of the filter and the outlet of the tank
Inside each wet cleaning tank, there's a filter net, and its job is to keep the bulk of the garbage out of the pump's thin channels, and over time, it builds a thick coating of lime, rust (if the tap water is hard) or mucus from detergents, and it creates resistance that the pump can't overcome.
Take the filter out of the tank. It's usually located at the base or in the neck. Wash it thoroughly under a stream of hot water. To remove lime plaque, soak the mesh in a solution of citric acid for 15 to 20 minutes. Do not use metal brushes, as they can damage the filter cells.
Also check the outlet of the tank itself. Often there is a pile or hair that acts as a plug. Use a toothpick or thin wire to clean the channel carefully. After cleaning, make sure that the water flows freely by tapping the valve.
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Use only distilled or filtered water to refill the tank, which will significantly prolong the life of the pump and prevent the formation of scale on the filter and membranes.
Diagnostics and maintenance of electronic pump
The heart of the humidification system is the electronic pump, which is what delivers pressure water to the mat. If the filter is clean and the air is removed, but the water is still not coming, perhaps the problem is in the pump itself. In the Roborock S5, S6, Xiaomi Mijia 1S models, the pump is often integrated into the tank housing or attached to it separately.
In long-term, a simple pump can get sour. Try applying a voltage directly to it (if you have electronics and multimeter skills), or start washing mode with your finger to the exit hole to feel the vibration. If the pump is humming but not pumping, it is clogged. If it is silent, perhaps the winding or contact has burned.
You can use a reverse flushing method to clean the pump, remove the pump from the tank (usually held on screws or latches) and blow it with compressed air or rinse it with alcohol to remove oxides. In some cases, soaking the working part of the pump in warm water with citric acid helps.
| Symptoms. | Probable cause | Method of decision |
|---|---|---|
| The pump is buzzing, there's no water. | Air traffic jam or blockage | Syringe purging, filter cleaning |
| Pomp is silent. | Break of contact or combustion | Trail check, pump replacement |
| Water drips spontaneously | Fluidity of the valve | Replacement of seals or tank |
| Mistake in the annex | Software or sensor failure | Setting reset, calibration |
Set up the intensity of the application
Sometimes it's technically good, but the software's settings limit the water supply. In the Mi Home or Roborock app, you can set a different humidity intensity for each room or area. If you set a minimum or off value for the current zone, the robot will report no water or simply not supply it.
Go to the cleaning map settings, check if the water limit for a particular type of coating is worth it (for example, for carpets, the supply often turns off automatically), try to increase the water supply level to "maximum" in the global settings and run the test.
Also worth checking is the firmware version of the device. Outdated software may contain bugs that misinterpret level sensor data. Update the firmware of the robot and the tank itself (if supported) through the app menu.
⚠️ Attention: When increasing the intensity of water supply, make sure that your flooring type (parquet, laminate) allows wet cleaning. Excess moisture can lead to bloating seams and soil damage.
Software reset and calibration of sensors
Robot vacuum cleaner electronics can accumulate cache errors. If physical methods don't work, try resetting completely. On some Xiaomi and Viomi models, this is done by pressing a combination of buttons on the body (usually a power button and a home return button simultaneously for 5-10 seconds).
Once reset, you need to reconnect the device to Wi-Fi. During the initial setup, sensors are often recalibrated, including tank and fluid level sensors. Remove the device from the Mi Home app completely and add it as new.
If the robot supports voice control, try to give a command to clean or check status. Sometimes the voice module can give more accurate information about the nature of the error than the dry code in the application. In some cases, it helps to completely discharge the robot's battery before turning off, and then charge to 100%.
☑️ Algorithm for water error
When Replacement of Components is Necessary
If all of these methods fail, there's probably a physical malfunction, most often the pump itself fails, the power supply is limited, and over time the membrane wears out or the engine loses power, pump replacement is an affordable procedure, original or quality analogues are easily found on marketplaces.
The second replacement is the tank itself. The plastic ages over time, the valves lose their elasticity, and the contacts become irreversibly oxidized, and if the tank is more than 2-3 years of active use, it is easier to replace than repair.
It is also worth checking the plume connecting the tank to the main board of the robot, it could rub or oxidize from moisture, carefully disassemble the top cover of the robot (with caution with warranty seals, if they are still relevant), and check the condition of the connectors.
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In 80% of cases, the problem is solved by cleaning the filter and removing the air traffic jam, and buying a new tank or pump is rarely required, only with prolonged neglect of maintenance.