Changed thermostat and heating element on Bosch WAA28165GB/24 washing machine, after machine was heating up/boiling water. Same problem occurred after new parts fitted. Shorted out electrics before and after parts replaced
Pump and motor working.
I originally thought, after extracting the heating element, which was heavily calcified (tenant had apparantly not used the 'Calgon' supplied), that this was the main cause of the water boiling. Yes, I also replaced the NTC Temperature sensor along with a new heating element (bought from 'espares', Genuine Bosch parts) - Result, water still boiling...
I missed out (possibly) an important detail.... There were fine black 'soot' like deposits on the drum ledge under the thermostat wiring and black 'spatters' on the back panel directly opposite the thermostat. Fine spread of 'soot' thoughout, although not heavy. No apparant burning to wiring any wiring or connections.
Was thinking about replacing the control board and wiring to NTC and to element in case of additional faults caused when machine shorted out after 'repairs' but have held fire until I get a 'continuity meter (from 'Maplins') and before this seeking advise as now. If it means a new control board (or 'ME 55E power board'), plus NTC, thermostat and wiring (after checking continuity) then O.K. with that (will go direct to 'Bosch' for spares next time). Hate to throw out, as I almost did.