BEST 510
TROUBLESHOOTING GUIDE
(cont.)
Troubleshooting
22
TROUBLESHOOTING CHART
Problem
Possible Cause
Action to Take
UPS cannot turn on
UPS rear panel main
Turn on switch.
and there is no alarm.
switch in off position.
Fuse open or circuit breaker
Replace fuse
tripped.
or reset breaker.
No incoming utility line
Check input
or abnormal input
power
frequency.
and wall socket.
UPS cannot turn on
Too low or high input
Test input
and alarm sounds
frequency.
frequency.
continuously
Too low or high input
Check input line
voltage.
voltage.
“BATTERY MODE”
No incoming line, very
Check wall socket
light is on when incoming
low or very high line
and test input
line is thought to be
line voltage.
normal.
Fuse open or circuit
Replace fuse or
protector tripped.
reset circuit
protector.
“FAULT” light is on and
UPS failure.
Call for service.
and alarm sounds
continuously.
Backup time is less
Battery is not fully charged.
Recharge the
than the rating.
Possible internal battery
battery for
charger failure.
at least 6 hours.
Re-test the
backup time.
If problem
remains, call for
service.
“BATTERY MODE” and
UPS is in battery mode
Check input
“BATTERY LOW/WEAK”
when input line fails.
power and
lights are on and alarm
Battery is near end of
wall socket.
sounds periodically.
discharge.
“OVERLOAD” light is on
Overloaded.
Remove the least
and alarm sounds
critical load.
continuously.
“BATTERY LOW/WEAK”
Weak battery.
Recharge battery
is flashing.
for 4 hours and
press the test
button again. If
the light keeps on
flashing, call for
service.
TABLE 7