Over the recent days, Corsair has seen a growing number of complaints on the fan controller on their Hydro Series H100 CPU water cooler within their forums.
Corsair has acknowledged there is an issue with some of the components included in a small number of H100 units with lot code 11359403 only. You can find your lot code on the printed label on your H100 box (See below image).
The issue seems severe enough that you are seeing the H100 being removed from the store shelves (as a sign of a partial recall by Corsair). Taking a closer look at the issue, it is related to the button on the unit that changes fan profiles. On affected coolers, the fan works at the default speeds no matter what the selected profile is.
Corsair is recommending "if you have this lot code, test your installed unit while the system is running by pressing the profile change button. If you push the profile button on the top of the cooling unit and the indicator lights change, but the fan noise remains the same, we recommend contacting Corsair technical support at email@example.com to arrange for some replacement parts that will correct this problem."
Read more on the issue at Corsair's Forum