hi
your problem is due to a small amount of grit entering into the solonoid valve and keeping the internal diaphram open allowing a small amount of water to pass through, the only answer is a new solonoid valve assembly, you can get one from triton see their web site click on spares and order. not to bad to replace but remember to turn off the water supply to the shower before you start.
regards cliff
cliff davies, October 2007
