Hi guys! Here is a system: 18HP+8HP. Works over 3 years. This year spring both inverter compressors came down. The reasons are: bad supply, garbage in pipes.How many R-410 was in system before - isn't known, there are no leaks. Also system works in winter in cooling mode all time (2 or 3 indoor units from 16). So, I think that work with abnormal low temperatures of outdoor air be the reason of broke too. Am I right?