What part do I need to fix my Aspirante shower, please?

Hi. My 10.5kW Aspirante shower has worked perfectly for 6 years then, yesterday, whilst it was on, there was a tiny 'pop' sound then the water immediately shut off. There's still power (ie the front light is on) but no sound from the pump nor any water. I've taken the front cover off, but there's nothing obviously 'burnt-out', so now I'm stuck... Any ideas would be welcome, please.