SU1000Li Manual
5
TROUBLESHOOTING
Symptom
Possible Cause
What To Do
UPS will not turn on
On/Off button not pressed
Press and release the On/Off button
to start UPS
UPS operates in battery mode only,
even though there is normal AC
present
Input AC circuit breaker is tripped
Reset circuit breaker by pressing
the plunger back in. If the AC
circuit breaker trips after UPS starts
up, reduce the load on the UPS
Fault LED is illuminated
UPS has detected an internal fault
Call for service
The AC Mode LED is illuminated,
but there is no output
The UPS is being controlled via its
communications port
Disconnect the computer cable
from the UPS and press the On
button. If UPS works normally, the
software has control of the UPS
UPS does not provide expected
runtime
The batteries may be weak or at the
end of useful service life
Charge the batteries for 8 hours and
retest. If the runtime is still less
than expected, the batteries may
need to be replaced, even though
the Weak/Bad Battery LED is not
illuminated.
Bad Battery LED is illuminated
Loose connections at the batteries,
Weak batteries, Bad batteries
Check battery connections, charge
the batteries for 8 hours, replace the
batteries.
Overload LED is illuminated
The load has exceeded the UPS’s
capacity
Check the specifications (See
Specifications section). Remove
part of the load
The AC Mode LED is blinking
once every second and the audible
alarm is silent
The UPS is operating in the Boost
Mode
The UPS is performing its intended
function
The AC Mode LED is blinking
twice every second and the audible
alarm is silent
The UPS is operating in the Buck
Mode
The UPS is performing its intended
function
