Let’s start by admitting that every inverter can be damaged by its environment. AC input voltage spikes, lightning strikes, floating earth connections, backfeeds, salt air, years of generator exhaust blown through the fan and yes, even animal activity – any of these things will eventually damage any inverter. And since we never know how the end-user will treat their inverter, we should all be ready to repair them at any time.
This is one of the reasons that we like Xantrex, Outback and Magnum inverters. Repair is generally based on board replacements. There are three major types of board in each inverter – the control board that usually has the user interface, the AC board that handles the switching between AC source and inverter, and the FET board with the field effect transistors that does the power conversion. A basic diagnosis usually indicates which of the boards ought to be replaced.
Every inverter has a warranty of at least one year and in most cases it is five years. Of course, events like those listed above are not covered under warranty. And normally an inverter should be diagnosed by a service centre to be covered under warranty. But things are often not that simple and even a service center can not always be sure of the cause. So we try to be liberal with warranty spares and in non-warranty cases we sell spares at $10 above our cost, to keep repairs as cheap as possible. We rely on the honesty and intelligence of our dealers to make the right decisions about warranty on behalf of the manufacturers.
That said, please remember that an inverter is not a surge suppressor or a power conditioner. Its purpose is not to control surges or spikes in your AC power. Those events will damage your inverter just as they will damage any electrical equipment. So please install voltage regulation between your inverter and your grid or generator. And make sure you have a good earthing system. Those two things will stop 90% of inverter failures in our experience.