Take the top cover off the brew area removing the two silver screws under the lid where the k-cup is located
Removed the zip tie leading to the water filter.
Lifted the black ring that holds the hose that goes to the needle and pull the hose up
Blew back down that line and lots of sediment will come out from behind the filter
Turn the unit on and let it brew hot water into the holding tank just so you can see if it is cleared
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Replaced everything to its original position including putting a new zip tie
on the line you removed.
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This is the third Keurig I have fixed that has had the same problem.
Generally, you have to de-scale the Keurig every three months
You don't have to use a whole tank of vinegar.
Put a 50/50 mix of vinegar and filtered water in the tank, run it once
Let the brewer sit for 45 mins so the vinegar can act on the scale
Run it a second time and let it sit for 15.
Then empty the tank, washing it throughly or you will get slime that builds up on the side and at the inlet at the bottom of the tank.
Now run the clean water through the Keurig for a few passes until you no longer smell vinegar.