Output of photovoltaic panels can suddenly decrease after 2 to 4 years of use without any apparent reason. In extreme cases, output can drop to 15 - 30% of the original value, typically it drops by 5 - 15% when compared to the original installed power. The reason is so called PID - Potential Induced Degradatiton. This phenomenon causes continual severe degradation of semiconductor material that solar panels are made of. This happens because of potential differential and the state of insulation resistance between the panel and the ground (or rather supporting structure). When taken care of in time, the process of silicon degradation can be reversed and the panel can be kept in good condition for the entirety of its estimated service time. PID healer is a device that can prevent solar panel degradation caused by aforementioned phonomenon and return the panel material to its original state. It measures panel insulation resistance and generates direct current pulses at night, which restores the semiconducting material. Properties of PID healer have to be defined with regard to the type of PV panel (polycrystalline, monocrystalline, CIGS) and to type, count, and output of inverters. One PID eliminator unit can service up to 3 inverters.
Inverters SMA, Vakon Adwance energy (Refusol), Sunnyways, Kaco, Delta, Fronius can be operated without switch-disconnector, feel free to ask about other inverters.