Posted Sun Oct 7, 2012, 10:05pm Subject: Fixed: Bezzera BZ02 not relieving grouphead pressure (portafilter sneeze).
When I purchased my Bezzera BZ02 espresso machine, I noticed that my portafilter "sneezed" a lot - almost every shot. When I tried to backflush the machine, the problem was amplified. I concluded that something was stopping my three way solenoid valve from releasing the group head pressure when I stopped the brew cycle.
Hoping it was not a sticking solenoid (could be pricy to replace), I unplugged the machine, removed the water reservoir.
Then I undid some screws holding the stainless steel warming rack, water tank lid, etc. in place. You want to get all the stainless steel off the TOP part of the machine, excluding the front where all the buttons are and the rear panel behind the water reservoir.
Then I gently popped off the plastic side panel. You can see the posts that click in to your machine on the photo so you know where to expect resistance. Pull the panel off one post at a time, leveraging as close as you can get to the post itself to avoid breakage.
Posted Sun Oct 7, 2012, 10:15pm Subject: Fixed: Bezzera BZ02 not relieving grouphead pressure (portafilter sneeze).
Still viewing the right hand side, zoom in a little to discover the culprit. Circled in red on the photo below, you can see that the drain line coming from the solenoid valve above and heading towards the drip tray below is kinked. I'm not sure if this is unique to my machine, but the tubing is way too long, causing it to kink easily and stay that way. If a person knew how to work with these types of fittings, he could cut the tubing shorter and reattach. However, we're going to opt for a safer fix for the mechanically declined.
Posted Sun Oct 7, 2012, 10:23pm Subject: Re: Fixed: Bezzera BZ02 not relieving grouphead pressure (portafilter sneeze).
Now the easiest fix in the world: a piece of plastic drinking straw is slit open (to "clip" over the tubing) and place over the kinked spot. The length of straw and placement will have to be determined by experimenting. Then it is secured by an inch or two of clear tape.
Voila! Now when I brew an espresso, my puck is dry as I could want, and the backflush solution drains into the drip tray when cleaning. There is now audible confirmation that my drain line is working as soon as I disengage the brew cycle. Before the portafilter would drip forever after each shot - now it only drips a few seconds after the shot stops.
I would be curious to know if other Bezzera owners have experienced this line-kinking problem.
Posted Mon Oct 8, 2012, 3:28am Subject: Re: Fixed: Bezzera BZ02 not relieving grouphead pressure (portafilter sneeze).
Nice writeup and good photos to document the problem.
If you remove one fitting at either end of the hose you should be able to slide the "nut" portion down the hose which will reveal that a ferrule sort of fitting is pushed into the end of the hose which the nut secures when tightened. If that piece was pulled out of the hose the nut could be slid off. A flexible metal spring cold be lid over the nylon hose to avoid kinks.
Posted Mon Oct 8, 2012, 2:37pm Subject: Re: Fixed: Bezzera BZ02 not relieving grouphead pressure (portafilter sneeze).
If you unscrew the nut it will should not hurt the fitting or seal. Slide the nut down the tube and you will see the part that is press-fit into the tube. if so, the you can should theoretically be able to cut the +/-5mm of the end of the hose of if necessary, rescue the internal part from the cut-off piece of tubing, and finish off as described above. According to your description, because it is just the bypass hose from the 3-way, it carries very little pressure so even a marginal seal should be sufficient.
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