N1C L-Series(1-3kVA) UPS
User Manual
5 Maintenance and Troubleshooting
37
No.
Phenomenon
Possible reasons
5
Buzzer long beeps, fault indicator is
on, inverter failure and UPS turns to
bypass mode.
(1) Load overload or output short circuit, UPS will
turn off automatically.
(2) Drive or power transistor failure.
(3) Main control board failure.
(4) UPS over-temperature protection
6
After starting UPS, UPS works
normally. When mains powers
down, UPS has no output.
(1) Battery failure.
(2) Battery charger failure. Generally, it can't charge
battery.
(3) Battery haven't been connected with UPS or
battery has been damaged seriously.
7
The input is normal, but buzzer still
beeps intermittently.
The mains voltage or frequency is out of the range of
UPS requirements.
8
Indicators on the panel are all off.
The wiring for display board is unreliable or fault.
If UPS failure, press " " button. It can view the UPS failure prompting on the LCD, which is good for
finding the fault source quickly.
The meaning of fault symbol and buzzer status in Table5-2.
Table5-2
The meaning of fault symbol and buzzer status
Fault symbol
Buzzer status
Meaning
Fault info.
page (page up
or page down
by "
"
button)
EPO
Long beep
UPS has emergency protection (if equipped with
EPO function), Bypass output and inverting
output are all closed.
BUS
Long beep
There has busbar voltage fault in the UPS, the
inverting output is closed.
TMP
Long beep
UPS has over-temperature protection; the
inverting output is closed. Please check if cooling
fan damage and air vents blocked.
OUT
Long beep
Output fault, please check if output is short-
circuited or the load is too large.
