The dual flush toilet mechanism serves two functions – filling and flushing. Over time, the dual flush mechanism needs to be adjusted to adjust the water level for an ideal flush.
Luckily, adjusting a dual flush toilet mechanism is an easy job. It’s something you can do by yourself within a few minutes, even without any plumbing skills.
There are usually three main parts to adjust – the toilet float, fill valve, and overflow tube.
The following steps will guide you on how to adjust the dual flush toilet mechanism:
How to Adjust Dual Flush Toilet Float?
The toilet float is a float cup or cylinder. It is the first fill mechanism and controls the water level in the tank.
It is attached vertically to the fill valve assembly. Its movement along the fill valve assembly controls the opening and shutting off of the fill valve.
If the toilet float is set too high, the water level in the tank will go above the overflow tube.
Excess water will go into the overflow tube, leading to a running toilet.
If it is set too low, the water level in the tank will be low, leading to weak flushing.
Carry out the following steps to adjust the toilet float:
Remove the Toilet Tank Lid
Don’t turn off the water supply valve or flush the toilet yet before removing the toilet tank lid.
Though the lids of single flush toilets aren’t connected to the tank, dual flush toilets have connected lids.
Some flush buttons are fixed to the lid and connected to the tank using two rods. And some are connected to the lid with a screw and can be unscrewed.
Either way, gently disconnect the lid before lifting it off the tank. Keep the lid somewhere safe.
Check the Water Level in The Tank
After removing the tank lid, check the water level inside the tank. Normally, the level of water should be at a half-inch to the top of the overflow tube.
Anything lower or higher than this is out of place, meaning the toilet float needs adjustment.
Adjust the Toilet Float Appropriately
If the water level in your tank is lower/higher than an inch below the overflow pipe, the float needs adjustment.
There is a long plastic screw along the float cup/cylinder. It’s attached to the toilet fill valve and toilet float and controls the height of the float cup/cylinder.
If the water level in your tank is lower, turn this adjustment screw slowly clockwise to raise the toilet float.
This will, in turn, raise the water level by allowing some water into the tank. If the water level is higher, turn it slowly anticlockwise to lower the float cup/cylinder. This will lower the water level.
Replace the Toilet Tank Lid
Now that you have adjusted the toilet float appropriately, it’s time to fix the flush buttons and replace the lid.
Don’t forget to properly clip the refill tube to the overflow tube. Ensure that the refill tube doesn’t go too deep into the overflow tube.
Ways to Adjust Toilet Fill Valve in a Dual Flush Toilet
The fill valve is the next fill mechanism to adjust. The fill valve can either be clogged or broken. The clogging of the fill valve is usually caused by a hard water supply. The following steps will guide you on how to fix the toilet fill valve.
Please note that adjusting a toilet fill valve is possible but purchasing a new one is the best option.
Turn off the water supply to the tank. You need to empty the toilet tank to access the parts in it. So, turn off the water supply valve to stop water inflow into the tank. The water supply valve is located behind the toilet bowl and connected to a rubber hose.
Flush the toilet. Push down the full flush button to completely drain the toilet tank.
Remove the tank lid: Carefully follow the step on how to remove the toilet tank lid above.
Check the fill valve. Carefully check the fill valve assembly. Is it broken, cracked, or leaking? If the fill valve is broken or cracked, replacing it with a new one is the only solution. Gently turn the broken fill valve anticlockwise and raise it to remove it. Some fill valves have a mounting nut, loosen the mounting nut to remove the broken fill valve.
Fit in the new fill valve, ensuring that it’s only slightly higher than the overflow tube.
Remove clogs. If the fill valve is not broken, clogs may be the problem. Remove the fill valve and check for the buildup of mineral deposits and debris. If there are clogs, use a brush and vinegar to remove them. After removing the clogs, replace the fill valve.
Replace seal. Sometimes a worn-out fill valve’s seal may be the problem. Get a new seal if you can’t afford a new fill valve assembly.
Check the height: Is the fill valve shorter than the overflow valve? You need to adjust the length of the fill value to go above the overflow tube by a half inch. Watch this video to understand how to adjust the length.
Ways to Adjust Dual Flush Toilet Overflow Tube
The overflow tube is the flush mechanism. It holds the flapper valve and collects overflowing water in the tank.
Ideally, it should be about an inch below the fill valve. Though an overflow tube can’t be adjusted, it can be broken and/or deteriorate.
When the overflow tube is broken or deteriorated, water will continuously run into the toilet bowl – causing a running toilet issue. In such as case, the overflow tube assembly will need a replacement.
How to Replace Overflow Tube?
The overflow tube in a dual flush toilet is in the flushing mechanism. In case the overflow tube gets damaged or is not working properly, you will need to replace the whole flush mechanism with a new one.
Since we have a separate article on replacing the flush mechanism, I’m not covering that again here. Please follow this guide to do the task.
To Summarize
There are a few ways that you can adjust your dual flush toilet if there are issues with the fill valve or overflow tube.
If the fill valve is clogged, remove it and check for mineral deposits and debris. If the overflow tube is broken or deteriorated, replace it with a new one.
Replacement is the best course of action as these things tend to not work properly for too long once they get damaged or worn out.