CLEAN FLASHING
Hamilton Beach Severe Scale Detected / Flow Restriction

“CLEAN” light flashes continuously and the coffee maker stops mid-cycle or refuses to start a normal brew.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Severely clogged heater tube, Blocked inlet screen at reservoir base, Mineral buildup on flow sensor, Partially blocked one-way valve

How to Fix / Troubleshooting

Safety first: Unplug the unit and allow it to cool completely before handling.

Deep descaling procedure:

  • Remove and rinse the removable water reservoir (if equipped) and check for a mesh screen at the outlet. Clean any debris with a soft brush.
  • Prepare a stronger solution: Use 2 parts white vinegar to 1 part water and fill to the MAX line.
  • Start a brew or CLEAN cycle and allow about 1 cup to run through, then turn the unit OFF and let it soak for 45–60 minutes.
  • Restart and complete the cycle, letting the rest of the solution brew through.
  • Flush with water: Run 3–4 full reservoirs of fresh water to clear vinegar and loosened scale.

Inspect for external restrictions:

  • Check the drip stop mechanism in the filter basket for sticking or partial closure.
  • Ensure the brew basket outlet is not clogged with coffee oils or grounds; clean with hot soapy water and a small brush.

If the CLEAN light continues to flash and the unit still stops mid-cycle, the internal heater tube or flow sensor may be blocked beyond home cleaning and the heater assembly may need replacement.

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Repair Difficulty

Medium 3/5

Required Part

Heater Assembly with Flow Path
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