A low float voltage alarm is displayed when the voltage supplied by the rectifiers is less than the configurable low float enclosure threshold is set at. The most likely cause of this is either a complete or partial AC fail. User should check to see if AC power is being supplied to the enclosure rectifiers. If there is AC power but alarm still appears, check to ensure all rectifiers are in working condition and the system is not in a battery discharge condition due to an excessive load. 

The threshold for low and high voltage can be set in DCTools. Under Alarms, scroll to the bottom, and expand the Alarm Configuration section. Under that section it is possible to change the values. Default low float is set at 52.8V and high voltage is set at 55.6V.