I am having a go at fixing mine as i seem to have similar symptom. I have tested all but two parts - a kind of semi-conductor that is located under the heater and the heating element itself. But the element seems to have continuity, the other dont. Also there seemed a dubious check on a sensor located right in the water inlet housing. It didn't seem to alter the relay(s) operation, and is probably a low water sensor. That may be it. My very learned friend will be able to help me tomorrow. So i'll be back!
Ilya, May 2007
