Cleaned it out last week coz I had a water flow prob. I had a build up in the inlet to mixing zone( my fault ) . So I had a drill in side n cleaned all the hard wall of. Anyway plugged it all back in set all back up switched it on and nothing. I'm running of a tank with pump. The leads are fine coz there are sum heaters on site running of 3 phase so I tested on them it they worked