We recently heard that a number of consumers were reporting problems with the fan controller on their H100. It looks like Corsair has confirmed there is indeed an issue and tracked it down to a single batch of coolers that are marked with lot code 11359403. The issue itself is related to the button on the unit that changes fan profiles. On affected coolers, the button doesn’t change the fan profile, and the fan works on the default speeds. The only way to fix the problem is to replace the unit, which is being done under warranty. You can find out more information about this ‘recall’ on this Corsair forum thread.
We have identified 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. 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.