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Over-pressure
Pump pressure climbs above 12 bar and stays there.
Category: Common Faults & Symptoms
The brew pressure climbs above 12 bar — sometimes pegging the gauge — and stays there during the shot.
Why it matters — Over-pressure stresses the pump, boiler seals, and group components. The shot tastes harsh because the puck is over-compressed and channelling badly. Long-term operation under over-pressure shortens the machine's life.
Good to know
- Cause is almost always a stuck-closed or misadjusted OPV. Adjust the OPV preload screw or replace the valve.
- Don't ignore over-pressure thinking "more pressure = stronger coffee." 9 bar is the design target; pressure above that doesn't extract more, it channels worse.
Related: OPV Parts