By Alice · Updated May 2026
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Your coffee machine sounds like it’s trying — you hear the motor humming, maybe a click or two — but nothing comes out. We’ve all been there. Most of the time it’s either an air lock trapped in the system or scale buildup choking the pump, and both are fixable without calling anyone.
If you skip fixing this, you’re stuck microwaving yesterday’s coffee or driving to a café every morning. Not ideal. The good news? You can usually get water flowing again in under an hour with tools you already have. Let’s figure out what’s going on and get you back to proper espresso.
What you’ll need
- Descaling solution (Urnex or white vinegar)
- Fresh water
- Large mug or container
- Microfiber cloth or towel
- Paperclip or needle (for clearing inlet)
- Owner’s manual (for your specific machine)
Step 1: Check the water reservoir
Make sure the tank is seated properly and filled past the minimum line. We’ve seen machines refuse to pump because the reservoir wasn’t clicked in all the way or the float valve got stuck. Give it a firm press until you hear or feel it lock.
Step 2: Clear any visible blockages
Remove the water tank and inspect the inlet valve where it connects to the machine — sometimes coffee grounds or scale flakes collect there. Use a damp cloth to wipe it clean, and gently poke a paperclip through the opening if you see buildup. Rinse the tank thoroughly before replacing it.
Step 3: Prime the pump to release air
Air locks happen after the machine runs dry or sits unused for weeks. Fill the reservoir, then run the brew or hot water cycle without coffee for 20–30 seconds. You might hear sputtering or see spurts of water — that’s the air working its way out. Repeat two or three times until flow is steady.
Step 4: Run a descaling cycle
If priming didn’t help, scale is probably blocking the pump or lines. Mix descaling solution per the bottle instructions (or use a 1:1 vinegar-water mix), fill the tank, and run your machine’s descale program if it has one. If not, just run brew cycles until the tank is empty. Yes, it smells like vinegar — open a window.
Step 5: Flush with fresh water
After descaling, refill the tank with clean water and run at least two full tanks through the system to rinse out any remaining solution. You don’t want descaler or vinegar flavor in tomorrow’s cappuccino. The water should run clear and odor-free by the end.
Step 6: Test with a normal brew
Load your portafilter or pod and make a test shot. If water flows smoothly and pressure feels normal, you’re done. If it’s still weak or sputtering, the pump itself may be worn out or there’s a deeper internal clog that needs professional help.
Pro tips & common mistakes
If your machine has been sitting unused for more than a month, run a priming cycle before you add coffee — air locks love stale setups. Some pumps need a few tries to catch, especially on older machines where the internal seals have lost a bit of grip. The dial on ours sticks slightly past 8 when priming — you get used to it.
A common mistake is assuming the pump is dead when it’s really just a 5-cent rubber gasket that dried out or a clogged screen you can’t see. Descale every 2–3 months if you have hard water, and you’ll avoid most pump drama. If you’ve descaled twice and still get no flow, or if you smell burning plastic, unplug it and call the manufacturer or a repair shop.
Related guides
- Which Maker is Best for Cuban Coffee: Electric, Pot or Espresso Machine?
- Coffee Maker Turns On But Doesn’t Brew? Here’s How to Fix It
- Why Does My Coffee Taste Bad From My Machine?
- How to Descale a Coffee Maker With Vinegar
Frequently asked questions
Why is my coffee machine making noise but not pumping water?
The pump motor is running, but water isn’t reaching it — usually because of an air lock or a blockage in the intake valve. Try priming the pump by running a few short brew cycles without coffee. If that doesn’t work, descale the machine to clear any scale buildup inside the lines.
How do I know if my coffee machine pump is broken?
If you’ve descaled, primed for air, checked the reservoir connection, and the machine still won’t pump after multiple attempts, the pump may be worn out. Another clue is a burning smell or the motor stopping completely. At that point, it’s usually more cost-effective to replace the machine unless it’s a high-end model worth repairing.
Can I use vinegar instead of descaling solution?
Yes, white vinegar works in a pinch — use a 1:1 mix with water. It’s cheaper but smells stronger and may take an extra rinse cycle to clear out. Dedicated descaling solutions are formulated to be gentler on seals and sensors, so if your machine is newer or expensive, stick with the real stuff.
How often should I descale to prevent pump problems?
Every 2–3 months if you have moderately hard water, or monthly if your water is very hard. Most machines will show a descale light, but don’t wait for it — regular maintenance keeps the pump, boiler, and lines clear. If you use filtered or bottled water, you can stretch it to every 4 months.
What causes an air lock in a coffee machine?
Air locks happen when the water reservoir runs completely dry, when you remove the tank mid-brew, or after the machine sits unused for weeks. Air gets trapped in the pump chamber or lines and creates a bubble that blocks water flow. Running several short priming cycles usually pushes it out.