Immersion heater fault

Hi any thoughts or insight into this fault much appreciated. So it's a 3kw immersion heater that's been causing the water to be scalding hot. It also blew a 15 amp rewritable fuse prior to me changing the stat earlier, anyway just had a text saying the water is still scalding and it's blown the fuse again. I'll go and have a thorough check tomorrow but I'm thinking the immerser may be on its last legs and needing completely replaced. Thanks for reading and look forward to reading any replies.