We have a camper with an older Phoenix Compact Multiplus 12/1200/50. It used to run flawlessly but lately, it randomly cuts off, even when there is only minimal load (fridge 135W) and even when connected to the grid. There is no PreAlarm, it goes straight to Alarm on stops supplying AC out. Switching it off and on again helps for a while, sometimes it runs for hours, other times only minutes. It doesn't appear to be related to a specific load as it works fine when switched off, then on again an d then connecting a (large) load, eg. a toaster.
It's quite annoying because the fridge only runs on 230V and hence stops cooling when the inverter cuts out, even though mains is connected. We could run the fridge on gas but would rather have the inverter operate reliably, of course.
Any ideas what may be causing it and how to fix it ?
Many thanks.