u/Disaster_Careful

Brand New Breville Dual Boiler (BES920) - Persistent Airlock & Overheating Issues (Steam from Group Head)

Hi everyone,

I’m looking for some help with a brand new Breville Dual Boiler (purchased in NZ, moved to India). I am currently dealing with a persistent airlock/vapor lock issue that I can’t seem to clear. I’m using a standard water purifier (non-RO), so conductivity shouldn't be the issue. The kitchen is air-conditioned and cool.

The Problem:

Overheating/Inaccurate Temp: The machine frequently jumps to 104°C or shows "instant" temperature changes (e.g., jumping from 87°C to 96°C in a second).

Flow Issues: I get "puffing" steam from the group head and hot water dispenser instead of steady water. Sometimes I get a few drops, sometimes a "rain" for 20ml, then it stops.

Pressure Gauge: The needle stays at zero, even with a cleaning disc in, though I do hear a "whoosh" of pressure releasing into the drip tray when I stop the pump.

Button Logic: 1-cup and 2-cup buttons work occasionally, but the "Manual" button seems to be locked out or unresponsive during these events.

What I have tried so far:

  1. Venting the Boilers: I have used the service screws (#1 and #2) behind the drip tray. I’ve seen heavy steam exit these screws. I’ve tried "burping" them by running the pump while the screws are cracked open until water exits.

  2. Solenoid Cycling: I’ve tried the "back-pressure kick" by running the pump against a cleaning disc and stopping it to cycle the 3-way valve. This improved the flow temporarily.

  3. Priming Tricks: I’ve tried the "Steam Wand Slingshot" (opening the wand and hitting the brew button) and holding the Manual button to force the pump.

  4. Hardware Checks: I’ve removed the shower screen and dispersion plate to check for blockages. The water tank is firmly seated, and I've tried priming without the water filter.

  5. Cooling Down: I am currently letting the machine sit OFF for several hours to allow trapped steam to condense and the NTC probes to dry out from potential internal condensation.

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u/Disaster_Careful — 22 days ago