Breville Dual Boiler BES900 / BES900XL — Basic Descaling & Flow-Restoration Technique

Over time, the Breville Dual Boiler can develop scale inside the water path, leading to weak flow, inconsistent steam performance, slow heating, or noisy pumps. This guide covers simple, external descaling and flushing techniques that help restore proper operation without disassembly. If you need model-specific diagrams or button layouts, you can check the Breville Dual Boiler user manual (available on ManualsLibraryy).

Tools & Materials

• Descaling solution (Breville-compatible)
• Large container or sink
• Clean microfiber cloth
• Fresh filtered water
• Group head cleaning brush (optional)

Difficulty

• Easy

Time Required

• 20–40 minutes

Step 1 — Prepare the Machine

• Turn off the machine and let it cool.
• Remove the water tank, empty it, and rinse it thoroughly.
• Remove the portafilter and any attachments.
• Place a large container under the group head and steam wand to catch the solution.

Step 2 — Mix and Load the Descaling Solution

• Prepare the descaling solution according to the instructions on the package.
• Pour it into the water tank and reinstall the tank.
• Power on the machine and allow it to fully heat before continuing.
• Heating helps loosen internal mineral deposits.

Step 3 — Flush the Brew Path

• Run the brew function for 10–15 seconds, then stop.
• Wait 20–30 seconds to let the solution soak in the internal lines.
• Repeat this cycle until the tank is halfway empty.
• If flow improves mid-process, that’s normal — scale is breaking free.

Step 4 — Flush the Steam Path

• Open the steam valve for 5–10 seconds.
• Close the valve and let the machine rest for 20 seconds.
• Repeat until another quarter of the tank has passed through.
• This helps clear the steam boiler inlet and wand lines.

Step 5 — Rinse Thoroughly

• Empty and rinse the water tank.
• Fill with fresh water only.
• Run two full rinse cycles:
  • One through the brew path
  • One through the steam wand
• Wipe any residue from the drip tray and group head.
• Proper rinsing prevents aftertaste and protects the aluminum and stainless components.