my triton t80 si shower in the last few days has started to cut out after around 2 mins,if you leave it for 10 mins and go back to it it works but does the same thing again.
if your talking about the water flow cutting out then it's the solenoid valve failing.
check the resistance on the solenoid valve in its failed state with a multi meter.
hi-spec plumbing & heating (essex), May 2010
might be the the temperature stat on the heating element giving a false signal the shower instructions should have fault finding diagrams displaying how to swap the part
