Bezzera Magica PID brew pressure problem

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
chunchiliu0816

#1: Post by chunchiliu0816 »

Hi all,
My Bezzera Magica PID is having a bit of a brew pressure problem. These few weeks during extractions, the brew pressure gauge on the front panel has been staying at around 2.5 bars resulting in watery extractions so I started a series of troubleshooting processes. Unfortunately, the problem still hasn't been solved yet and I hope someone can help me with this.

Symptoms:
1. Channeling seen in the puck with watery extractions (18g to 36g takes around 12 seconds)
2. Brew pressure stayed at around 2.5 bars while brewing

Troubleshooting:
1. Descaling: I descaled the E61 group head a couple of times
2. Verifying the coffee grinder: I borrowed a working Sette 270 (I grind with Sette 270) to rule it out
3. Verifying the brewing pressure: With a backflush disk, the brewing pressure struggled at 2-4 bars for a bit and eventually went all the way to 10.5 bars (my dialed in default settings)
4. Verifying the group head flow rate: 4oz/18-20 seconds
5. Verifying the OPV valve flow rate (set at 10 bars): 1oz/ 12-14 seconds
6. Verifying the portafilter/portafilter basket/shower screen/group gasket/mushroom valve: I replaced all these parts with brand new identical ones
7. Verifying the vibration pump: I read it somewhere in the forum someone had an identical problem and the pump was accountable eventually. Therefore, I replaced the ULKA pump

I ordered a group head pressure gauge which will be arriving in a few days. I would like to know what the pressure is in the group head. I'm suspecting that somehow the pressure in the group head got really high and caused the channeling and the low pressure. Does that make sense? Any suggestion is appreciated. Thanks!