Hey there
I too have had the same problem with the Roca Flush.....just figured what the problem is.....and how to resolve it.....
*IF its not the rubber washer (which I have been told needs replacement every year, depending on the water softness/hardness), then the water pressure in the cistern (tank) is too high.
*This can be adjusted by the water inlet tube. There is an adjustable cap on the pipeline (inside the cistern) which is ribbed....try lowering the cap to a lower rib-line=this will ensure less water is filled inside the cistern after every flush.
* You may need to "fine tune" the measurement (various line markings)
This will make the ease the water pressure on the rubber washer....and will ensure the water will remain totally in the tank rather than slowly seeping through into the toilet bowl.
Took me ages to work it out, and was driving me potty (excuse the pun)....
THIS WILL WORK!!!
It finally makes sense....!!
Kris Stenholm
August 2009