I was hoping to get some help troubleshooting this problem with my espresso machine. It has been working wonderfully the past few months since I bought it used off of craigslist. I immediately backflushed it with purocaf, and try to take good care of it. I only make a few shots a day, so it's not under heavy use. I try to backflush with water after I'm done using it each day, and every couple…