☕ If your Breville Barista Express BES870 is suddenly making weak coffee, losing pressure, or behaving strangely around the drip tray, the 3-way solenoid valve is one part worth checking.
It is a small but important valve inside the machine. After each shot, it releases pressure from the grouphead and sends leftover water safely into the drip tray. When it becomes blocked, worn or electrically faulty, the machine can no longer control water flow properly.
Common signs of a failing BES870 solenoid
🔧 You may notice one or more of these symptoms:
- Very little or no water coming through the grouphead
- Weak coffee and a pressure gauge that barely moves
- Water continuing to drip from the grouphead after a shot
- An unusually wet puck
- Steam, hissing or water where it should not be
- Water behaving oddly in the drip tray during or after extraction
- The power or safety switch trips when you press the shot button
- The machine works sometimes, then loses flow again
A blocked shower screen, stale coffee, scale or a badly adjusted grind can also cause poor extraction, so it is worth checking the simple things first.
Machine trips the power when you press the shot button
⚡ This is another fairly common BES870 fault. If the machine turns on normally but trips the power as soon as you press the espresso/shot button, the 3-way solenoid coil can be shorting when it is energised.
Because the valve is activated during brewing, the fault may only appear when you ask the machine to make coffee — not when you first switch it on.
There are other possible causes of power tripping, so don’t keep resetting the safety switch and trying repeatedly. But if it happens specifically when the shot button is pressed, the solenoid is a strong suspect and should be tested or replaced.
⚠️ If the machine trips the safety switch, stop using it and unplug it. Do not continue cleaning cycles or repeated testing. Arrange professional diagnosis.
Before replacing anything
The cleaning and water-flow checks below apply only when the machine is not tripping the power and there is no internal leak. If either is happening, stop using the machine and arrange a repair.
🧼 Start with a proper cleaning cycle using grouphead cleaning tablets and descale the machine if it is due.
If water flow is still poor, remove and clean the shower screen, and make sure you are not using coffee that is ground too fine. If the machine is still struggling after that, the solenoid may be the culprit.
Why do these valves fail?
Scale and coffee residue are the usual offenders. Over time, they can clog the tiny passages inside the valve. The electrical coil can also fail.
The frustrating part is that a solenoid can look perfectly fine from the outside while not opening or closing properly inside the machine.
The fix: replace the 3-way solenoid
⚙️ If cleaning has not restored normal flow, replacing the valve is usually the reliable solution.
Our replacement 3-way solenoid valve suits the BES870, BES870XL and BES876 Barista range.
💧 Also inspect the BES840/BES870/BES876 solenoid connector. A cracked or leaking connector can cause the same water-flow symptoms and may damage the new valve if it is not replaced.
If you are opening the machine for this repair, it is also sensible to inspect the group seal and hose clips while you are there. A little preventative maintenance now can save another strip-down later.
Not keen on repairing it yourself?
🚗 Bring it into the workshop, or contact Matt about a repair and Matt can help work out whether it is the solenoid, pump, scale buildup or something else.
A BES870 with a solenoid fault is often very repairable — no need to throw away a good coffee machine.
More help with your BES870
For other symptoms and simple checks, read our Breville Barista Express BES870: 10 Common Faults and Fixes.
📮 Outside Perth? Enquire about a post-in repair from anywhere in WA →
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