I have a Triton Aquatronic 2 Ultra electric shower where the pressure relief valve has operated.
I can see that the device can be removed from the shower and is listed as a replaceable part.
It may be a bit of a hassle to remove unless I can find my right angled screwdrivers so before I dismantle it can the valve be reset or does it have to be replaced?
Currently with the shower hose removed (removing any restrictions) and the shower running without heating the pressure relief is still open.
(And before anyone advises, yes the shower is now electrically isolated both by the pull switch being off and the dedicated MCB in the consumer unit switched off)