Start here
A steady combined CLEAN/DESCALE indicator on the matching BES870 revision calls for the descaling instructions rather than assuming the flashing-light cleaning cycle will clear it. Confirm the label first: the lamp behavior and the name on your machine both matter.
Which observation matches?
Choose the closest observation. The complete decision list remains below.
Combined CLEAN/DESCALE label, steady light
Review the descaling section for that exact revision and the required approved agent.
The same combined indicator is flashing
Start with the flashing cleaning-light article, not a descaling shortcut.
You completed only the group-head tablet cycle
That does not establish completion of the separate water-path descaling procedure.
The lamp remains steady after a documented full descale
Record the stages completed and final state. Ask support before adding another dose of chemical.
Safe checks, in order
- Check the rear/bottom label safely with the machine off, cool and empty enough to handle; do not tilt a hot full brewer.
- Confirm whether the last maintenance used a cleaning disc/tablet or a tank descaling solution. Those are different operations.
- Follow the exact manual for solution preparation, water-filter handling, outlets and rinse stages. Do not improvise a chemical recipe.
- After the full procedure, discard the waste liquid and confirm normal operation before making a drink.

What a persistent light does and does not tell you
It tells you the expected maintenance state has not cleared. It does not tell you how much mineral deposit remains, and it cannot be used as a test of chemical residue. Review the completed steps before diagnosing a failed component.
When not to descale immediately
If the machine has no flow, an internal leak or an uncontrolled steam release, do not use a chemical cycle to see what happens. Document the separate symptom and obtain support. A safe, functioning machine with a routine maintenance prompt is a different case.
Use the matching manufacturer illustrations
The source links below identify the relevant manual or support page. No verified exact-model hands-on repair video is claimed on this page. Use the written decision list without imitating a different machine.
Open model-specific referencesStop and obtain help when
Stop for a failed rinse, unknown chemical mixture, blocked flow, leaking or a warning pattern not described by the matching manual.
Questions this diagnosis does not skip
Can I add more descaler to make the light go out?
No. Use only the prescribed concentration. More chemical is not a diagnostic method.
Is this the same as FLUSH on the Barista Pro?
No. Use the Barista Pro procedure for its own display and maintenance system.
References and evidence
- Breville Barista Express BES870 instruction book, X26Check the exact BES870 regional revision; not the Express Impress.
Manufacturer facts and procedures are referenced above; the observation comparisons are our diagnostic synthesis, not proof of a failed component. Photos are illustrative, not evidence of hands-on testing. Editorial standards | Report a correction.