Hi everyone

The group output of my trusty Nuova Simonelli Oscar II has started to falter - it will initially pump out water, then it will start getting quite steamy until there is only steam coming out, this will happen for a few seconds and then the water flow will start again for a while before repeating.

I have tried brewing with the top off to see if there is anything obvious going on, but there was nothing I could spot. Does anyone have any idea why all this air is getting into the HX line? Not sure what else to say, so let me know if you have any questions!

Thanks for your thoughts.