Your domestic water diaphragm is gone, not the easiest to do on this model. I spent more than 2 hours doing 1 last week, you have to dismantle a few water carrying components to get to it and run the risk of creating a water leak unless replacing all the washers and 'o' rings that come with a diaphragm and service kit. I wouldn't tackle this yourself unless you are an engineer to be honest.
Taliskerman, June 2011
