DIAGNOSIS Mineral scale and biofilm accumulation in the polypropylene water reservoir. This does not affect taste directly but can impede water flow and is unsanitary.
FIX Use Technivorm's recommended descaling procedure. For manual cleaning: unplug the machine. Mix a solution of 1 part white vinegar to 2 parts warm water. Fill the reservoir halfway. Use a soft bottle brush to scrub the interior walls, especially around the bottom outlet. Let the solution sit for 15 minutes. Empty and rinse thoroughly 3-4 times with clean water.
IF THAT DIDN'T WORK For stubborn film, use a diluted solution of citric acid (1 tablespoon per liter of water) as a stronger descaling agent. Never use abrasive scrubs or steel wool, as they will scratch the plastic.
HEADS UP Do not immerse the entire machine in water. Avoid using bleach or harsh chemical cleaners, as residues can damage internal seals and affect coffee taste. Regular monthly cleaning is advised.