Moccamaster Internal Leak in Water Circuit

Water leaks from the bottom of the coffee maker during or after brewing

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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

Cracked aluminum heating block, Split silicone hose, Loose hose clamp or connection, Damaged reservoir grommet or seal

How to Fix / Troubleshooting

Safety: Unplug the machine immediately and do not operate it while leaking. Water near live electrical parts is dangerous.

  • External inspection: Remove the carafe and wipe the base dry. Fill the reservoir with cold water and observe where water appears. Note if it leaks only when brewing or also when idle.
  • Access internal plumbing: Remove the base cover and, if needed, the side/top panels to expose the heating block and hoses.
  • Check hoses and clamps: Inspect all silicone hoses from the reservoir to the heating block and up to the riser tube. Look for splits, pinholes, or loose clamps. Replace damaged hoses and tighten or replace clamps.
  • Inspect heating block: Look for hairline cracks or corrosion on the aluminum heating block. If water seeps from the block itself, replace the entire heating block assembly.
  • Check reservoir seal: Inspect the rubber grommet or seal where water exits the reservoir. Replace if hardened, cracked, or deformed.
  • Dry and test: Thoroughly dry all components, reassemble, and test with water only while monitoring for leaks.
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Repair Difficulty

Hard 4/5

Required Part

Silicone Water Hose
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