How to fix Stylus Banksia toilet not flushing?

handymum8

Hi there, we have a back to wall Stylus Banksia WC with the dual flush, approx 12 years old that won't flush. At first thought it was a blockage but have plunged, augered etc and doesn't seem to be anything stuck. Water goes away on flushing but then comes back to fill the bowl, bringing back whatever was flushed down. It then gradually drains away. Our other toilet in the house is flushing fine so can't see that it could be a blockage further along the pipes. Could it be something else eg. a mechanism in the cistern? Any help greatly appreciated. thanks!

JacobZ

Hi @handymum8,

A warm welcome to the Bunnings Workshop community, it is fantastic to have you with us.

It sounds like your toilet is experiencing a drainage issue rather than a complete blockage. Since you've already plunged and augered without success, the problem is likely due to ventilation, a partial obstruction, or a malfunctioning flush mechanism.

One possibility is a ventilation issue. If the plumbing vent (usually on the roof) is blocked, it can create a vacuum that prevents the toilet from flushing properly. This can cause water to drain slowly and even come back into the bowl before gradually disappearing. A simple way to check is to run water in a nearby sink and listen for gurgling when you flush the toilet. If you suspect a vent blockage, spraying water down the vent pipe from the roof might help clear any debris, such as leaves or bird nests.

Another potential cause is a partial blockage in the toilet’s internal trap or just downstream in the waste pipe. Even though you've used a plunger and auger, some obstructions can persist, especially if there's a buildup of debris or mineral deposits. To test this, try pouring a large bucket of water directly into the bowl. If the water drains quickly, the issue is likely with the flushing mechanism rather than a blockage. However, if it backs up, a deeper obstruction may still exist.

The flushing mechanism inside the cistern could also be the culprit. If the toilet isn't releasing enough water into the bowl during a flush, it might not generate the necessary siphon effect to carry waste away efficiently. Check that the inlet valve is fully open and allowing the cistern to fill properly. Also, inspect the flush valve seal, as a worn-out or stuck seal can prevent a full flush. If your toilet has a dual-flush button, make sure it's engaging properly and not getting stuck in a half-flush position. Replacing the flush valve seal or the entire outlet valve may resolve the issue if it's related to the cistern.

If you try these things and still have issues, then it is likely you will need to contact a plumber for their assistance.

Let me know if you have any further questions.

Jacob