Your Sirena's motor is humming, or sounds different
Stop the machine and unplug it. Do not use it "one more time" to finish the room.
That is not a turn of phrase to sell you a repair: it is the point at which this fault is decided. One single use after the humming appears is enough to make the damage irreversible, and the difference between the two outcomes is 210 €.
What that noise is
The motor has one component made on purpose to wear out: the carbon brushes. They are two blocks of graphite held by a spring, resting on the armature — the part that spins — carrying current to it by rubbing against it. Wearing out in place of the copper is their job.
As they get shorter, the metal holder that carries them moves closer to the armature. Until it touches it. The noise you hear is that contact: metal rubbing on copper where graphite used to rub. From that moment on, every minute of running scores the armature a little more, and those scores do not come out.
On a Sirena in regular use the brushes reach the end of their life after a few years. It is not a defect: it is scheduled maintenance, like brake pads.
Why we don't sell the brushes
We are often asked, and the answer is no, for a practical reason: to get to them the machine has to be opened and the motor taken out. That is bench work, with the machine in pieces, and doing it at home voids the warranty. The power cord and the main board, on the other hand, are reached by removing the rear cover only — and those you will indeed find in the catalogue, with a video.
What the motor overhaul covers
Taking the motor out in the workshop, new genuine brushes, cleaning the armature, and checking performance on reassembly.
If the armature is still sound, we add two years to the warranty on the motor. That is the case for anyone who switched off in time.
If the armature is already scored, we tell you straight away, with photographs, before going any further: we fit nothing without letting you know. At that point a new motor costs 210 € instead of 360 €, because the 150 € of the overhaul comes off — and on a new motor the warranty is five years.
If you would rather not replace it, we still fit the new brushes and send the machine back to you working. It is an honest stopgap: the armature stays marked, the new brushes will wear out faster, and in that case there is no warranty extension.
Right now
Leave the machine switched off and message us on WhatsApp: we'll tell you how to send it in.