Phoenix multiplus 12/2500/120 in my narrowboat. I've noticed during the night that every 29 seconds, the unit gives a brief (1 second) hum/buzz. After a while, the intervals are short to just a few seconds but quickly reverts to the approx 29 second intervals.
Have not noticed this on other inverters (Victron and MAstervolt).
Does this indicate something could be wrong? There are issues as the dip-switch settings are not saved, including a reset to default.
Thanks