LEGRAND NUMERIC HP i 33 40 kVA Series User Manual page 88

Table 7-1. Trouble shooting
No. Abnormal phenomena
At mains status, the UPS works
10
normally, once power outage, the
UPS works normally but load
system halts.
FAULT indicator of a power unit
11
is on.
81
Possibl e reason
The grounding is improper and the float voltage between
neutral wire and grounding wire is too large.
The power unit is faulty, replace it in time.