Toto Flush Valve Troubleshooting – Problems, Reasons, and Solutions

Nothing can be worse than a not working flush valve.

Think about a situation.

You are pooping in your bathroom with great pleasure in the morning. After finishing, you press your TOTO flush button and it is not working.


You just enter your bathroom and see your TOTO flush is leaking water.

How will you feel?

Of course, nasty and frustrating.

Now you have two options. You can either call a plumber and wait for an hour or solve the problem yourself. Knowing about TOTO flush valve troubleshooting will help you overcome the situation. You can save your time and money at the same time. Besides, solving the problem will prevent replacing the flush soon.

Toto Flush Valve Troubleshooting

TOTO Flush Valve Troubleshooting – Problems and Solutions

Many different problems can occur with the TOTO flush valve. We will discuss some common problems and their solutions with reasons. Let’s dive into the main part.

TOTO flush valve does not flush

The most common problem with the TOTO valve is that it does not flush. Many reasons. Let’s check each of the problems and solutions. 

The valve in the water supply or control panel stop is turned off. 

You need to check whether the main valve and control stop. You will find the valve in the main water supply. Open the valve or control stop and check. If it is turned off, make sure to turn it off. Then install the valve once again.

No electric connection is there.

If the valve is not connected through the wire, it will not flash as well. Check whether the wire is connected or not. If not, simply connect the wire. It should not run smoothly.

Stain in the infrared sensor’s surface 

If the surface located in the infrared sensor is stained, chances are high that your valve will not flush. To solve the problem, simply clean the surface using a piece of cloth. You can also use a brush to clean it. 

The infrared sensor’s surface is destroyed. 

Sometimes, instead of getting dirt, the surface of the infrared sensor can get destroyed. If that happens, your valve won’t flush no matter what. To solve this problem, contact the distributor for replacement. You can also purchase a new one.

The front of the sensor surface might be reflective

If the sensor has a reflective surface, it won’t work as well. In that case, the only option you have is to replace the sensor. You can either ask from a distributor or purchase a new one.

Batteries are not installed in a wrong way

Sometimes, the batteries are installed in the wrong way. Or maybe you have not installed it yet. Check the batteries and make sure they are installed and in the correct way.

Dead batteries

Even if the batteries are installed in a proper way, they can be dead. In that case, the flush will not work. Check the battery and solve the problem.

Clogging in the small holes in the solenoid diaphragm

If there is any clogging inside the holes in the solenoid diaphragm, your flush might not work. Check the holes carefully and clean the holes with a cloth or wire.

TOTO Flush Keeps Running

You may also experience your continuous running of TOTO flush. It happens for many reasons. Let’s check the reasons and solutions.

Clogging in the piston hole

The piston hole grows dirt slowly and gets clogged after a certain period. Simply turn off the water supply and check the hole. If you find any dirt, clean the dirt and it should get the job done.

Dirty sealed piston area

Along with the piston hole, the sealed piston area may grow dirt as well. Cleaning the area will solve the problem. 

Dirt sealed solenoid diaphragm

Dirt in the sealed solenoid diaphragm may cause continuous water running. Make sure you clean the sealed solenoid diaphragm area and strainer properly.

TOTO Flush Valve Discharge Too Much or Too Little

Another common problem you may see is your valve discharges too much or little. Only one reason can be responsible for that.

Improper adjustment of the screw/handle in control stop or piston valve

The screw or handle determines the discharge. You can simply adjust the screw to control the discharge. Use a screwdriver to adjust it.

Too low flow in TOTO flush valve

The flow might be too low in the valve. There can be multiple problems related to this problem. So follow the process below.

Low water supply pressure 

If the water pressure level is below 10 PSI, it may cause low water flow. You need to hire a plumber to increase the flow. Trying yourself may make the problem worse.

Narrow control stop

Sometimes, the control stop is narrow which causes low water flow. Simply adjust the control stop and open it properly.

Too high flow rate

Opposite to a low flow rate, you may experience high water flow. The main reason is;

Unadjusted control stop

If the control stop is too open, it may increase the water flow. In that case, simply narrow down the stop and decrease the water flow to a convenient level.

TOTO flush valve turns on or off without flushing

Sometimes, you may see the flush valve turn on or off automatically without flushing. The reasons can be;

Lack of proper slack in flapper chain

The main reason for this auto shut on or off is the lack of proper slack. To solve the problem, adjust the proper slack.

The flush valve flapper is dirty

A dirty flush valve flapper can cause the problem as well. Simply inspect the flapper and see whether it is dirty or not. If it is dirty, wipe with a piece of cloth.

The red light in the sensor blinks

Sometimes, you may see the red light in the sensor blinking. The reason is’

Weak battery

Check the battery. The main reason for this problem is the weak battery. In that case, replace the battery.

Prevention to the problems

Prevention is always better than cure. So taking preventive measurements will help you get rid of this problem. So here are the preventive measurements for you.

  • Inspect the flush valve regularly. If you see any signs, take action immediately.
  • Keep your valve clean. Use a simple piece of cloth and wipe down the dirty area.
  • Use replace the battery regularly when you find it dead.
  • Make sure you check the battery status. Blinking light indicates low battery. 
  • Always take help from professionals in severe problems. You may make the problem worse in some cases. So it is wise to call a plumber.


It is frustrating when you find your TOTO flush valve does not work or leak water. Knowing TOTO flush valve troubleshooting will help you solve the problem and remove the frustration. Since the flush valve is prone to wear and tear, you may find this problem often.

You can solve the problem by spending a couple of minutes. The time is worth investing since it can save you money and the time that you need to invest to hire a plumber. However, make sure you hire a plumber if the problem is severe. You cannot solve the problem on your own all the time.

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