What to Do When Your Automatic Toilet Won’t Flush?

Automatic toilets are supposedly the peak of hygiene standards because they require no tactile input to work. But this automated system is prone to malfunction when you need it most. The sensors might not work, or the flush could activate before you’re done with your business. Many people don’t know what to do in that situation, and you are probably one of them.

Troubleshooting an automatic toilet is not difficult. Most of the time, it’s a case of you blocking the sensor somehow. However, if the problem is too severe, you might need to tinker with the valves.

There are many reasons behind a malfunction, and you need to approach the issue differently for each of them. It would be best if you had some insight into how an automatic system works. This article will teach you what to do when your automatic toilet won’t flush.

Inner Workings Of An Automatic Toilet

The Automatic toilets activate with a sensor. An infrared sensor detects objects that come within its proximity. The sensor then activates the flushing mechanism once your body leaves the proximity.

automatic toilet sensor
Image from DadHelpful

The motion sensor considers you are using the toilet only when you are within detection range. This range, however, is not uniform for all models. Some sensors will start the flush while you are still sitting. That usually happens if you lean forward too much and go out of its range.

Some toilets also have a backup option for the sensors. In this case, the system will automatically activate the flush after a while. It happens when the system thinks there’s something wrong with the sensory input. So it flushes just to be safe.

Last but not least, there’s also a manual sensor that should activate when you pass your hand over it. This one is usually placed on the lid or on the sides.

What Causes Flushing Issues With Automatic Toilets?

Most people consider automatic toilets a game-changer. It has almost no negatives and is excellent for maintaining hygiene. But some pesky problems do pop up from time to time. Here are some of the common causes behind such issues:

1. Blocked Sensor

If your flush is not working, the cause is almost always a blocked sensor. The sensor at the back requires precise input to initiate the color. The sensor’s surface is always in clear sight, which makes it easy to temper.

automatic toilet sensor blocked by a tissue
Image from DadHelpful

Blocking the sensor is so easy that even dust and dirt accumulation can mess with it. Sometimes decorations on the toilet lid can hang down and stop the sensors.

2. Issues With The Power Supply

Most toilets use standalone batteries or a direct connection to the electrical supply to draw power. A bit more advanced ones use a mixture of both. But power can run out, which will inevitably stop the flush from working.

Most toilet sensor batteries are good for 300k or so flushes. The number can vary depending on the brand, but it’s usually around that range. The direct electrical ones use your home’s electricity to power the flush. So it will stop working when your power goes out unless you have a backup battery.

3. Damaged Component

Sometimes an automatic toilet’s issue might be more complicated. The sensors are merely triggers, and the flushing mechanism is a separate entity. There can always be some plumbing issue with the flush.

Wiring issues show up quite often with automatic toilets. Disconnected or damaged wires will stop the sensors from working. That will also prevent your attempts at flushing.

4. Toilet Flusher Was Installed Too Early After Last Flush 

The general guideline is to install the toilet flusher at least 5 seconds after the last time you flushed. Or not the sensors won’t calibrate properly and flushing issues will occur.  

How To Fix Flushing Issue Of Automatic Toilets

There are many ways to troubleshoot a faulty automatic toilet. Here are some common fixes you should try before calling in a professional:

automatic toilet flusher

1. Reinstall The Flusher 

There might be some calibration issue with your flusher and it is completely fixable. Just take out the flusher, wait for 15 seconds or more after the last flush and then reinstall it. Here’s how to do it. 

Step 1: Take out the battery compartment from the auto flush unit. 

Step 3: Find the nut connecting the auto flush unit to the flush valve. 

Step 4: Unscrew the nut and free up the auto flush.  

Step 5: Now remove the auto flush unit from the flush valve. 

Step 6: Let any water dripping from the vale to leak out. 

Step 7: Fit the sensor body back into the flush valve and screw in the nut to install it.

Step 8: Reinstall the battery compartment into the flush sensor body. 

Step 9: Installing the auto-flush properly should automatically start up the auto-flush. 

Don’t worry about turning off your water system or anything like that. You can just simply take the unit off and reinstall it back in. 

2. Clean The Sensor

As I mentioned earlier, the sensors can quickly turn blind even with the slightest obstruction. A small tissue paper on the sensor will effectively stop it from flushing. Doing so is a life hack even. 

Some toilets might flush while you are still on the seat. Putting toilet paper on the sensor stops that from happening. So, you can see how easy it is to block the sensor.

That is why your first troubleshooting method is checking if something is blocking the sensor or not. Clean The sensor’s surface thoroughly with a dry cloth, and try flushing again.

3. Replace The batteries

Sometimes, the power supply is the root cause of an automatic toilet not working. The ones that run solely on battery need replacements. You happened to be the unlucky one who needed to replace the battery. The replacing process is easy, and you only need a 1/8″ hex wrench and a flat screwdriver. 

Turn off the water supply first. Then take off the lid. You will then need to disconnect the wires connecting the batteries and solenoid. Next, take out the battery compartment. The whole unit should come out with a slight pull.

You need to take the battery out from the battery slot and replace it with a new one. Place the battery unit back and reconnect the wires.

4. Replace the Flushometer

An automatic toilet’s flushing mechanism relies on a solenoid valve. It is more commonly known as the flushometer. It is the switch that starts and stops the water flow. Unfortunately, it can have issues and need replacement.

The process of replacing the flushometer is not all that hard. You will first need to turn the valve on the side. Then open the lid and disconnect all the wires you see. Please take a photo of it beforehand so you know which one goes where. 

Pull the solenoid out gently, and replace it with a new one. Reconnect the wires, and you’re good to go.


And that, my friends, is what to do when your automatic toilet won’t flush. There are plenty of reasons why your automatic flush could be malfunctioning. But hopefully this guide was able to help you with fixing your issue. 

Try to keep the components clean, especially the sensors and valves at all times with frequent maintenance cleaning. That will prevent any sticky situations in the future. Also, remember to replace the battery regularly, even before it runs out. Best of luck to you on fixing you issue. 

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