Breville BES900 โ Technical Repair Dossier
240V/50Hz | Australia/NZ Region
This dossier was compiled with AI assistance from community repair knowledge, forum posts, and field measurements. Resistance values, part codes, and wiring references are indicative only. Always verify against your specific unit before ordering parts or performing electrical work. Specifications may vary between production runs. Work on mains-connected appliances carries risk of electrocution and fire โ if in doubt, engage a licensed appliance repairer.
Machine Overviewโ
| Attribute | Detail |
|---|---|
| Model numbers | BES900BSS (brushed stainless) |
| Voltage / Frequency | 240V / 50Hz (AU/NZ) |
| Power consumption | ~1500W |
| Boiler architecture | Dual boiler โ independent brew boiler (PID) + steam boiler |
| Portafilter | 58mm commercial-style |
| Water tank | 2.5L removable |
| Pump | ULKA EP5 vibratory (brew), ULKA NME (steam boiler fill) |
| Temperature control | PID for brew boiler; pressure stat for steam boiler |
| Display | Digital LCD |
| Country of sale | Australia, New Zealand |
Field-Verified Component Valuesโ
Measured by Pertl across multiple units, March 2026.
| Component | Value | Notes |
|---|---|---|
| Brew boiler element | 102 ฮฉ (~565W at 240V) | |
| Steam boiler element | 60.8 ฮฉ (~948W at 240V) | |
| ULKA EP5 pump (brew) | Diode mode: 0.79V fwd, OL rev | Resistance mode reads Mฮฉ due to internal 1N4007 diode โ always use diode test |
| ULKA NME pump (steam fill) | Diode mode: 1.6V fwd, OL rev | Higher reading = higher-impedance coil, not a fault |
| Thermostat | 0.1 ฮฉ | Passes continuity |
| Thermal fuse | 0.4 ฮฉ | Passes continuity |
| Degraded EP5 (example) | Diode mode: 1.35V, resistance 7.7 Mฮฉ | Partial winding breakdown โ replace |
- Healthy: 0.69โ0.8V forward in diode mode
- Degraded: Above ~1V forward = winding breakdown starting
- Dead: OL both directions
Diagnostics Menuโ
The BES900 has two hidden diagnostic modes: the Fault Log (error codes + cup counter) and the Self-Check Mode (live NTC temperature display). These are not documented in the user manual.
Fault Log (Error Codes + Cup Counter)โ
This mode lets you view the shot counter, scroll through stored error codes, and clear them.
How to enter:
- Make sure the machine is off (standby โ power button not lit, but plugged in at the wall)
- Press and hold the Menu, Up, Down, and Exit buttons simultaneously
- While still holding all four, give the Power button a short press
- The display will activate in fault log mode
Once inside:
| Action | How |
|---|---|
| View cup counter | Press Menu โ displays shot count รท 10 (e.g. 0420 = 4,200 shots) |
| View error codes | Press Menu again to toggle to error code view |
| Scroll error codes | Use Up / Down buttons โ display shows XX:YY where XX = error code, YY = number of occurrences |
| Clear error codes | When ErSt is displayed, press and hold Hot Water until it beeps (clears codes only, not cup counter) |
| Exit | Press Exit to leave diagnostics and boot the machine normally |
The BES900 has six buttons: Menu, Up, Down, Exit, Hot Water, and Power. Button labels may vary slightly between production runs.
Error Code Referenceโ
| Code | Meaning | What to check |
|---|---|---|
| 00 | Steam boiler NTC error | Steam NTC thermistor โ open circuit, shorted, or connector loose |
| 01 | Steam boiler NTC error | Same as 00 โ secondary detection for steam NTC fault |
| 02 | Coffee boiler NTC error | Brew NTC thermistor โ open circuit, shorted, or connector loose |
| 03 | Coffee boiler NTC error | Same as 02 โ secondary detection for brew NTC fault |
| 04 | Group head NTC error | Group head thermistor โ check wiring and connector at group |
| 05 | Group head NTC error | Same as 04 โ secondary detection |
| 06 | No water in steam boiler | Water level probes not detecting water โ check probes, ground strap, and NME fill pump operation |
| 07 | Water overflow in steam boiler | NME pump running too long / level probes stuck reading "empty" โ check probe continuity and fill solenoid |
| 08 | Coffee water flow failure | No flow detected during brew โ check flow meter, EP5 pump, 3-way solenoid, and water tank seating |
| 09 | No water in coffee boiler (startup) | Brew boiler dry on power-up โ check water tank, inlet valve, and brew boiler fill path |
| 10 | Coffee NTC over-temperature | Brew boiler overheated โ check PID board, relay stuck closed, NTC accuracy |
| 11 | Steam NTC over-temperature | Steam boiler overheated โ check pressure stat, relay, NTC accuracy |
| 12 | Group head NTC over-temperature | Group thermistor reading dangerously high โ check NTC, wiring, and whether group is actually hot |
Codes come in pairs (00/01, 02/03, 04/05) for each NTC sensor. If you see occurrences on both codes in a pair, that NTC is almost certainly faulty โ not an intermittent wiring issue. A single code with low count might be a loose connector or one-off glitch.
Self-Check Mode (Live NTC Temperatures)โ
This mode displays real-time temperature readings from all three NTC sensors. Useful for verifying sensor accuracy, diagnosing heating faults, and confirming boiler operation.
How to enter:
- Turn the machine off at the wall (not just standby โ full power off)
- Press and hold the Exit and Manual buttons simultaneously
- While still holding both, turn the machine on at the wall
Self-check menu sequence:
Press Menu to step through each screen in order:
| Screen | Display | Meaning |
|---|---|---|
| 1 | A18 (example) | Firmware version โ yours may differ |
| 2 | 50 | Hardware/board parameter |
| 3 | All segments + LEDs light up | Display test โ verifies all LCD segments and indicator LEDs are working |
| 4 | H HH | Self-check mode active โ ready for temperature readings |
Diagnostics (from the H HH screen):
Press Menu + Down together for the first reading, then Menu to step through each subsequent screen:
| Screen | Display | Meaning |
|---|---|---|
| 5 | Temperature (e.g. 95) | Coffee (brew) boiler temperature โ enter with Menu + Down |
| 6 | Temperature (e.g. 134) | Steam boiler temperature |
| 7 | Temperature (e.g. 87) | Group head NTC temperature |
| 8 | F F + solenoid clicks | Solenoid test โ actuates the 3-way solenoid valve (you'll hear it click) |
| 9 | Eep eras (flashing) | EEPROM erase โ โ ๏ธ factory reset option, clears all stored settings |
The Eep eras screen will factory reset the machine if confirmed โ erasing programmed shot volumes, temperature offsets, and all user settings. Do not press any confirm button on this screen unless you specifically want to wipe everything back to factory defaults.
Expected temperature ranges (fully heated, normal operation):
| Sensor | Normal range | Investigate if |
|---|---|---|
| Coffee boiler | 90โ95ยฐC | Above 95ยฐC or stuck at ambient |
| Steam boiler | 125โ135ยฐC | Above 135ยฐC or not climbing |
| Group head | 85โ93ยฐC | Above 93ยฐC or much lower than brew boiler |
If any NTC reads well above these ranges, the sensor may be faulty (reading low resistance = board thinks temp is lower than reality = keeps heating). Shut down and test the NTC with a multimeter before continued use โ a stuck-on heating element is a fire risk.
Known Faultsโ
Steam Boiler Fill Pump Runs Continuouslyโ
Symptoms: The small NME pump (steam boiler top-up) runs non-stop even though the steam boiler has plenty of water. Machine otherwise functions normally.
Diagnosis:
- Pulled water level probes โ looked clean visually
- Continuity test on the small probe was intermittent โ would pass then fail on wiggle
- Board kept losing the water level signal โ defaults to "keep filling"
Root cause: Faulty/degraded water level probe โ intermittent continuity at the probe connection.
Fix: Replace all 3 probes. Pump behaviour returns to normal immediately.
Notes:
- If probes look clean, don't stop there โ test continuity end-to-end (probe tip to board connector)
- Check the ground path (circuit completes through water to boiler body) and ground strap on boiler housing
- If wiring and probes all good, suspect the level detection circuit on the control board (common if steam has been leaking onto the PCB)
Relationship to BES920โ
The BES900 is the predecessor to the BES920. They share the same dual-boiler architecture, similar control boards, and largely the same diagnostic interface. Key differences:
| BES900 | BES920 | |
|---|---|---|
| Brew element | 102 ฮฉ (~565W) | 77.6 ฮฉ (~742W) โ more powerful |
| Steam element | 60.8 ฮฉ (~948W) | 47.7 ฮฉ (~1208W) โ more powerful |
| Water tank | 2.5L | 2.0L |
| PID control | Yes | Yes โ refined firmware |
| Diagnostic codes | Same 00โ12 | Same 00โ12 |
| Service menu access | Same button combo | Same button combo |
Most diagnostic procedures, error codes, and repair approaches transfer directly between the two models. Element resistances differ, so don't use BES920 values to diagnose a BES900 (and vice versa).