DualLite LSN - 109. Maintenance Bypass Switch Phase Check

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109. Maintenance Bypass Switch Phase Check
If you are not using a bypass switch with the LSN inverter system, the phase check is not necessary, so you can
skip this section and go directly to Section 110 to complete the system start-up. If the LSN unit does have a bypass
switch, complete the following phase check once you have made all of the terminal strip connections and installed the
batteries.
CAUTION: Before you switch the bypass switch from “UPS” to “AC Line,” make sure you
follow the steps below to check for correct operation.
1. Makesurethemaincircuitbreakerattheloadservicepanelisoff,ormakesuretheconnectedloads(protected
equipment)cannotreceivepowerfromtheLSNinvertersystem.Turnthebypassswitchtothe“OFF”position.
AttheACservicepanel,applypowertotheLSNsystemandthebypassswitch.TurntheLSNMasterON/OFF
Switch to the "ON" position. Turn the bypass switch to the "ON" position.
2. Press the precharge switch for ten seconds. Release the precharge switch and immediately turn the LSN Main
DC Switch to the "ON" position.
3. Turn the Main AC Switch inside the LSN system to the "ON"position.Theloads(protectedequipment)shouldstill
be off at this time. After a short startup, the READY LED and AC-ON LED will illuminate. The LSN inverter system
is ready to supply output power.
4. Make sure the voltage from the LSN system to the connected loads is close to the voltage from AC line to the
bypassswitch.(Theremaybeslightdifferences.)Tomeasurethis,useanACvoltmetercheckthevoltage
between the following points on the bypass switchterminalstrip.(Seetheterminalstriplabel).Recordthe
voltages below.
AC from LSN Output AC Line Input
 (60Hz208or240VAConly) 7to8_________VAC 11to12_________VAC
 (60Hz208or240VAConly) 6to8_________VAC 10to12_________VAC
 (Allothervoltages) 7to8_________VAC 11to12_________VAC
Thevoltagesrecordedintherstcolumnshouldbesimilartothevoltagesinthesecondcolumn.Thevoltagesmay
vary slightly. If the voltage readings vary more than a few volts, shut down AC line and the LSN system. Check
all connections at the terminal strip, and correct any wiring problems.Ifhelpisrequired,contactDual-Lite’s
Technical Support Center at 1-800-848-6439.
Important: If the AC Input voltage is 208 volts, you will normally measure 88VAC between output terminals 6 and
8. Never connect any 120-volt load to the 88-volt terminals.
5. If a Break-Before-Make type bypass switch is being used, proceed to step 8.
If a Make-Before-Break bypass switch is being used, make sure the AC voltages from the LSN system output and
the AC line input are in phase. To do this, measure the AC voltage between the following points on the bypass
switchterminalstrip.Thesemeasurementsshouldnotbemorethan100VAC;ifmeasurementsexceed100VAC,
contactDual-Lite’sTechnicalSupportCenterat1-800-848-6439.
 (60Hz208or240Vonly) 8to12_________VAC
 (Allothervoltages) 7to11_________VAC
6. Measure the AC voltage between the following points on the bypass switch terminal strip. This reading should not
exceed1VAC;ifmeasurementsexceed1VAC,contactDual-Lite’sTechnicalSupportCenterat1-800-848-6439.
 (60Hz208Vor240V)   6to10_________VAC
 (60Hz120Vor50Hz220/230/240VAC) 8to12_________VAC