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Transfer to Maintenance Bypass from On-Line
• Prior to transferring the maintenance bypass to the
bypass mode, the UPS must be in bypass. Verify that
the UPS does not have a bypass out-of-sync or
bypass voltage out-of-tolerance alarm prior to
transferring.
• If no alarms are present, transfer the UPS to bypass
by placing the bypass/UPS switch on the back of the
UPS in the bypass position. Verify the L1-L2, L1-N
and L2-N output voltages, with a DVM, are as per the
customers specifications.
• Rotate the maintenance bypass switch counter-
clockwise to the test position. Open the UPS output
breaker and silence the alarm. Power is still being
powered to the input of the UPS in the test
position.
• Continue rotating the maintenance bypass switch
counter-clockwise to the maintenance position. The
UPS should now shut off and input power has been
removed. Open the input, output and battery breaker
prior to servicing the unit.
Transfer to Test from Maintenance Bypass
• After preventive maintenance or repairs have been
performed, it is important to test the UPS prior to
placing it on-line. Please use the following steps to
test the UPS without transferring on-line.
• Close the Battery breaker on the UPS. Place the
bypass/UPS switch on the back of the unit in the UPS
position.
• Rotate the bypass switch on the maintenance bypass
clockwise to the Test position. Close the input
breaker on the UPS.
• The UPS should now be going through its normal
testing and start-up procedure. Follow the LCD
screen instructions.
• After the output breaker is closed and the ON button
is pressed, the unit should return to the Normal
Operation screen. Proceed to the meter screen on
the LCD. Verify that meters are within operating
specifications.
• Return the LCD to the Normal Operation screen.
Transfer the UPS to bypass by placing the
bypass/UPS switch on the back of the unit in the
bypass position.
Transfer to On-Line from Test
• Always verify that the UPS is in the bypass mode
prior to transfer to On-Line position. Rotate the
bypass switch to the On-Line position.
• The customer may now bring up their connected
critical loads. Always energize the load on bypass,
either UPS internal bypass or maintenance
bypass.
• After the load is up and operating, the UPS may now
be transferred on-line. Transfer the UPS to the UPS
mode by placing the bypass/UPS switch on the back
of the unit in the UPS position and pressing the ON
button on the front of the unit.
TROUBLESHOOTING/WARRANTY
Troubleshooting
Troubleshooting should only be performed by a trained
engineer authorized by. If you cannot resolve a problem,
consult Liebert immediately at 1-800-222-5877. Do not
continue to use the maintenance bypass cabinet if it is not
performing according to specifications.