Hello,

Our ECM Giotto machine is about 2,5 years old and was working fine until about 3 months ago. The problem is as follows: when the machine stands a while (f.E. warming up) and the lever is pulled, it takes a long time before the water is coming. There is a hissing sound and it takes approximately 10 sec's before water is running. After the coffee is ready, the machine is leaking water out of the infusion piston (the pipe where the water is coming out after backflushing) for a long time, about half an hour (a little bit of water every few seconds). If the machine was in use and a second shot of coffee is made the machine is working fine, only the dripping of water remains.

Anybody has an idea what it might be? The machine is well taken care of (descaling, cleaning) and just had a minor maintenance (rings replaced and cleaning).

Your description sounds very much like Ruppert's in Constant dripping from E61 grouphead, i.e., the upper valve gasket is not sealing. If this seal fails, water drips from the heat exchanger. Eventually it drains enough that a bubble of steam forms, which explains the hissing sound and the delay before water runs from the group (eventually the grouphead will cool down because the thermosyphon circuit is broken).

You could just replace this one seal, or get a grouphead rebuild kit and replace them all.