If you have a push button operated cistern, there's a few different possible causes.
The most likely being what is known as a base sealing washer. Over time this small rubber washer will deteriorate and often warp, resulting in an adequate seal no longer being made once the flush valve closes. We stock many different makes an models of flush valve, as such the base sealing washers are not universal or interchangeable.
Another possible cause is the flush valve is getting stuck open. This can be a problem with the internal mechanism which lifts the flush valve, or a fault with the cable or button attached to the valve.
It is also possible that there may be an issue with your inlet valve. Many flush valves have what is known as an internal overflow - whereby if the cistern doesn't stop filling; the water will spill over into the overflow assembly on the flush valve and into the toilet pan. This is unlikely as typically this won't just be a small trickle, there would be quite a large flow of water constantly in the toilet pan.
Most push button operated flush valves feature a 2-part design, allowing you to replace the complete assembly or the base sealing washer without having to remove the cistern.
If you'd like us to identify which flush valve you have, please send us an image of your flush valve via email and we'll get back to you.
This is almost always indicative of diaphragm washer failure. Lever flush syphons have what can only be described as a piston-like assembly on the inside of them. At the bottom of this assembly is a very thin, flexible plastic membrane.
Over time as the toilet is flushed, holes will start to form in this membrane. Eventually resulting in complete failure. This diaphragm washer is very easy to replace if you have a 2 or 3 part syphon as there will be no need to remove the toilet cistern.
If you'd like us to identify which syphon you have, please send us an image of your syphon via email and we'll get back to you.
An easy way to test which part needs to be replaced is by blowing down the pneumatic tubing attached to your flush valve. If the valve lifts without any issue, then your push button needs to be replaced as it is no longer producing enough pressure to lift the valve.
If the flush valve doesn't lift properly or doesn't lift at all, you'll need to replace the flush valve or the pneumatic assembly which lifts it.
If you'd like us to identify which flush valve or button you have, please send us an image of your flush valve or button via email and we'll get back to you.