Bezzera BZ10

Bezzera BZ10: Expansion Valve Adjustment

Below are photos of how to go about accessing and adjusting the expansion valve seat.

Tools Needed:

  • 3mm Hex Driver
  • Adjustable wrench

1. Remove the panels.

2. Locate the Expansion Valve on the right side of the machine.
Image from iOS (66)-1

3. Use an adjustable wrench to adjust the amount of pressure being cut down from the vibratory pump - counterclockwise will increase pressure at the brew group, while clockwise will decrease pressure. To adjust, turn the machine back on (this is fine to do while the panels are off as long as the reservoir is seated securely in the bracket with all hoses in place), take note of the pressure on your brew gauge while backflushing, adjust the expansion valve accordingly, and retest. Ideally, we will want to see 10.8 bars of pressure while backflushing - you'll notice that this measurement will come down to about 9 bars when brewing espresso ground coffee.

Image from iOS (69)