Put another way, particle-free, organosilane-based sealants, which seal multiple leaks against high operating pressures on a long-term basis, need moisture to cause the necessary chemical reaction to solidify and create a long-lasting, strong bond around a refrigerant leak hole. That moisture doesn’t come from within the system however, but rather outside the system. The escaping cold refrigerant gas lowers the ambient air’s dew point near the hole and causes moisture to condense. These water droplets react with the sealant composition to form a solid chemical weld over the leak point.
Moisture within the system is a totally different story, however. Besides its counterproductive nature that leads to metal corrosion, drier capacity depletion, acid production, waxing or wax-like films and other problems, moisture inside the system is never a good refrigeration environment whether sealants are present or not.