Wonder if any one can help? I had a call to an Isar M03100 which had stopped working, I replaced the main pcb but noted that there was also water dripping from the lip seal on the plate to plate heat exhanger which I also fixed, boiler working fine..Then a few days later got a call to say boiler sometimes stops, the display shows a horizontal line with the burner light on, and other times works fine.I also changed the cable between the display and pcb and the mounting part which the display plugs into as they were slightly corroded, has any one come across this before? could it be the control unit causing the problem now? advice appreciated.