Breville Dual Boiler (BES920) Self Check Mode: How to Access the Hidden Diagnostic Menu

Diagnostics
Written by Brenton Jory

The Breville Dual Boiler (BES920) has a hidden diagnostic mode that most owners never know exists. It shows you what's happening inside the machine, including the water level probes and live temperature readings from both boilers and the group head. It's a useful first step when tracking down heating problems, checking a machine after a descale, or confirming a sensor is reading correctly.

It isn't covered in the user manual, and there's one trap you need to know about before you start.

⚠️ Read this first

Holding MENU + UP + DOWN + EXIT together erases the machine's memory (the screen will show ErAS / EPP). This resets the machine to factory defaults and wipes your shot counters and custom settings, and it can't be undone.

Press only the buttons listed below, one step at a time, and don't experiment with other buttons while you're in Self Check Mode.

How to enter Self Check Mode

  1. Turn the machine off at the wall.

  2. Press and hold the EXIT and MANUAL buttons together.

  3. While still holding both buttons, switch the machine back on at the wall.

  4. Press MENU until the screen reads LLLL or HHH. This screen shows the water level probes: the brew boiler probe and the two steam boiler probes.

  5. Press MENU and DOWN to show the brew (coffee) boiler temperature.

  6. Press MENU again to show the steam boiler temperature.

  7. Press MENU again to show the group head temperature sensor (NTC).

The menu also includes a pump test and a display test, which flashes every segment, light and button so you can spot one that isn't working.

To leave Self Check Mode, switch the machine off at the wall. It will start up normally next time.

What the results tell you

  • Probe readings that don't make sense (for example, a boiler showing no water when it's full) usually point to a faulty or scaled-up water level probe. This is a common problem after a descale.

  • A temperature reading that's well off, or doesn't change as the machine heats up, can point to a faulty temperature sensor (NTC), heating element, thermal fuse or control board.

These faults are best diagnosed properly before you start swapping parts, because the wrong part can be an expensive guess.

Need a hand?

Caffitech repairs Breville machines down to component level, including control board diagnosis and repair, and we stock parts and service kits for the Dual Boiler. If your BES920 is playing up, get in touch

Brenton Jory