How to Adjust the G-Max Flushing System

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You can adjust the G-Max flushing system.
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TOTO's G-Max flushing system is a bit different from most brands. The main difference is the fill valve portion of the system. Unlike other fill valves, the G-Max float sits inside a housing, resulting in fewer loose moving parts. As with any other system, adjustments become necessary over time.


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When the toilet takes a long time to fill, it is usually due to sediment buildup inside the valve. If you have a toilet that runs or does not seem to flush completely, it might be necessary to adjust the water level. Adjusting the G-Max flushing system correctly addresses both of these problems.


Slow-Fill Adjustment

Step 1: Turn Off Water Supply

Turn off the toilet water supply at the cutoff valve behind the toilet. Lift the lid off the toilet tank and place it on a flat surface out of the way.

Step 2: Remove Float From Fill Valve

Pull the refill tube away from the G-Max fill valve with your fingers. Hold the shaft of the fill valve and unsnap the top valve cover with your free hand. Press the sides of the float arm on the top of the G-max fill valve together with your fingers. Lift the float out of the valve.


Step 3: Remove Center Tube

Hold the fill valve shaft once more and twist the cap on the valve counterclockwise until it releases from the valve. Remove the cap completely from the valve. Lift the center tube out of the fill valve with your fingers.

Step 4: Hold Cup Above Fill Valve

Position a coffee cup upside down over the fill valve and hold it with one hand above the fill valve. The lip of the cup should be even with the top of the fill valve. Turn on the water supply slowly and allow the water to run through the valve. The cup prevents the water from shooting all over the place.


Step 5: Run Water Until Clear

Continue running the water until it runs clear with no debris. Shut off the water supply again, once all debris is cleared from the G-Max fill valve.

Step 6: Remove and Rinse Strainer

Pull the strainer out of the center of the center tube with a pair of needle-nose pliers. The strainer is visible at the bottom of the tube. Rinse the strainer and the center tube cap under running water to remove any sediment. Insert the strainer back into the center tube.


Step 7: Replace Center Tube and Cap

Insert the center tube into the center of the fill valve. Place the cap over the center tube and twist it clockwise until it locks into place. The two ribs on top of the cap should point to the float chamber.

Step 8: Replace Float in Float Chamber

Place the float into the float chamber and push down until the float arms engage around the cap. Push the G-Max top cover over the top of the valve until it locks into place. Push the fill tube over the nipple on the valve.


Step 9: Turn on Water Supply

Turn on the water supply and put the lid back on the tank.

Water Level Adjustment

Step 1: Locate Water Level Mark

Remove the lid from the toilet tank and set it to the side out of your way. Find the water level mark on the G-Max overflow tube.


Step 2: Mark Float Housing Water Level

Make a mark on the float housing with a permanent marker at the current water level. The float housing does not have a stamped mark, and the permanent mark gives you a point of reference the next time adjustment is necessary as well.

Step 3: Unlock Fill Valve

Turn the top half of the G-Max fill valve counterclockwise to unlock it. Allow the top of the valve to rise up until the mark on the float housing is level with the water level mark on the fill tube. Push down if the current water level is too high.


Step 4: Lock Valve Into Position

Twist the top half of the fill valve clockwise to lock the valve into position. Flush the toilet and allow the tank to fill. Check the water level and make adjustments as necessary. Put the lid back on the tank once adjustments are complete.