Hello, We have a Triton Enrich electric shower which is about 2 years old & recently started having an issue with it. Basically once you have finished your shower & turn it off there is a humming noise & a dribble of water continues coming out. When your actually using the shower it all works fine, Just when you turn it off that it has this humming sound. To stop it we have had to turn it off at the switch on the ceiling.
There's a solenoid valve that opens to let water in and shuts to cut off the water supply, seems to me that it could be scaled up or may be some debris is inside preventing it from closing properly. https://www.tritonshowers.co.uk/electric-showers/enrich-electric-shower.html?spares=true