Works too well, can't stop windows from sweating!
I don't know much about humidifiers other than they are rarely needed and most folk around here would rather there was a lot less humidity., especially considering how easily black mould grows and how injurious to health that can be.
Those few people living with an unsuitable heating system in a badly designed house usually find it is adequate to have a water feature in the lounge or to balance a bowl of water on a radiator.
Certainly when the windows sweat to such a degree, especially if you have double glazing, the humidity must be well above the comfort range, above 70%, and probably well into the moist range of 80% - 90%. Higher than that and any exertion becomes decidedly unconfortable...
I am guessing the humidistat is either faulty or cannot work because the humidity is already too high. I suggest you need to check the humidity in your home with an accurate independent humidity meter before you go further...
17 hours ago