Keurig Coffee Maker F18 Error Code Fix

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What This Error Means

F18 on a Keurig coffee maker = Water Flow / Fill Fault.

Translation: the machine tried to move water through the system, did not see enough flow, and shut itself down to protect the heater.

Most of the time this is caused by scale, a clogged inlet screen, an air-locked pump, or a weak pump / bad flow sensor.

If your particular model’s manual defines F18 slightly differently, it will still point to the same area: water in, water through, or water pump control.

Official Fix

This is basically what Keurig and the manuals tell you to do:

  • 1. Power reset it.
    • Turn the brewer off, unplug it for at least 5 minutes.
    • Plug it back in, turn it on, and try a plain hot-water brew (no pod).
  • 2. Check the water source.
    • Reservoir models: Remove the tank, rinse it, then fill it to the MAX line with fresh water and reseat it firmly. Make sure the float (if present) is not stuck at the bottom.
    • Plumbed-in / office models: Make sure the shutoff valve is open, any external filter head is not bypassed or clogged, and building water is actually on.
  • 3. Clean the inlet screen.
    • Pull the reservoir off.
    • Look for the little mesh screen or plastic strainer where the machine sucks water in.
    • Rinse it under running water and brush off any slime, scale, or debris.
  • 4. Clean the needles / outlet path.
    • Use a straightened paper clip to gently clear the top and bottom needles where the pod sits.
    • Rinse by running a few “no pod” brews.
  • 5. Descale it fully.
    • Run a full descale cycle with Keurig solution or white vinegar (follow your model’s instructions for timing and dilution).
    • Then run at least 2–3 full tanks of plain water through to flush.
  • 6. Try again.
    • Run several large “hot water only” cycles back-to-back.
    • If F18 is gone, you were dealing with restriction or scale.
    • If F18 keeps coming back, the official answer is: stop and call Keurig or an authorized service center. They will talk pump, flow meter, or control board replacement.

The Technician’s Trick

Here is how a bench tech actually attacks an F18 that survived the official steps.

  • 1. Prime the pump (fixes air lock and light blockage).
    • Unplug the brewer.
    • Remove the water tank and fill it with warm (not hot) water.
    • Snap it back on firmly so you know the bottom valve is opening.
    • Now, with the brewer plugged back in, start a large “no pod” brew.
    • While it is trying to pull water, gently lift and drop the reservoir a few millimeters a few times. Do not yank it off, just “burp” it. This often frees a stuck check valve and clears an air pocket.
    • If it suddenly roars to life and starts flowing, let it finish, then run 3–4 more water-only cycles.
  • 2. Force-feed water through the inlet (more aggressive, but effective).
    • Unplug the brewer again.
    • Pull off the reservoir.
    • Use a turkey baster or large syringe filled with water.
    • Press the tip firmly against the machine’s water inlet (the round rubber seal where the tank normally sits) and squeeze water into it.
    • You are pushing water through the pump and flow meter manually, which can dislodge small clogs and remove air.
    • Reinstall the tank, plug the unit back in, and try a large hot-water cycle.
  • 3. Tap test for a sticking pump.
    • While a brew or hot-water cycle is trying to start and you hear humming but no flow, smack the side of the machine near the lower rear with the heel of your hand. Not a punch, just a firm tap.
    • If flow suddenly starts, your pump is weak or sticking. It may work for weeks, but it is on borrowed time.
  • 4. Internal inspection (only if you are handy and out of warranty).
    • Unplug it, remove the case screws, and lift the shell carefully.
    • Check for kinked hoses, scale blocks at fittings, or a leaking pump.
    • If hoses and screens are clean but F18 stays, techs usually swap the pump and flow meter as a pair and call it done.

Is It Worth Fixing? (The Financial Verdict)

  • ✅ Fix: Brewer under ~5 years old, otherwise in good shape, and F18 clears with cleaning, priming, or a single pump/flow-meter replacement (parts are cheap, labor is the main cost).
  • ⚠️ Debatable: Mid-age unit (5–7 years), heavy daily use, and you are paying a shop; if parts + labor land over ~60% of the price of a new Keurig, think twice.
  • ❌ Replace: Older than ~7 years, signs of leaks or burned connectors, or F18 comes with other random errors or tripping breakers — do not sink real money into it, replace the machine.

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