Pre-Start-Up Checklist; Special Tools Required; Start-Up Procedure; Voltage Imbalance - LG GEN2 Series Installation And Operation Manual

Rooftop dedicated outdoor air systems
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Start-Up Unit

Pre-Start-Up Checklist

 Remove any foreign objects that are located in the
unit.
 Check all fasteners, set-screws, and locking collars
on the fans, bearings, drives, motor bases and
accessories for tightness.
 Rotate the fan wheels and energy recovery wheels
by hand and ensure no parts are rubbing.
 Verify diameter seal settings on the energy recovery
wheel.
 Filters can load up with dirt during building
construction. Replace any dirty pleated filters and
clean the aluminum mesh filters in the intake hood.
 Verify that non-motorized dampers open and close
properly.
 Check the tightness of all factory wiring
connections.
 Verify proper drain trap installation.
 Check condensing fans for any damage or
misalignment. Spin the blades and make sure they
don't contact any parts and are free turning without
any resistance.
 Look over the piping system.
 Inspect all coils within the unit. Fins may get
damaged in transit or during construction. Carefully
straighten fins with a fin comb.
Electrical
 Disconnect and lock-out all power switches.
 Verify control wire gauge.
 All field-mounted sensors and instruments are
installed and wired.
 Unit controls are off.
 Electrical service matches unit voltage.
 Electrical field wiring is complete.
 All electrical connections are tightened.
 Compressor and motor breakers or fuses are open
(disabled).
 Main power is wired to the disconnect.
 Discharge air sensor is installed per wiring
instructions.
 Space temperature and humidity sensors are
installed per if selected with unit.
Compressors
 This unit contains a crankcase heater for each
compressor which needs power supplied to it
24 hours prior to start-up. If start-up is scheduled in
24 hours, unlock the disconnect power and
energize unit.
 Compressor shipping brackets are removed if
provided.
IG Furnace
 If there is an indirect gas-fired furnace in this unit,
refer to the manual provided with this unit for Pre-
Start-Up information.
 Gas piping is complete and gas lines are purged.
 Gas venting is in place.
Hot Water/Chilled Water Coils
 Chilled water piping system is complete.
 Hot water piping system is complete.
 Control valves are installed, wired, and operating
properly.
 Water coils are balanced to design GPM.
 Water system is free of air.

SPECIAL TOOLS REQUIRED

• Voltage Meter (with wire probes)
• Amperage Meter
• Pressure Gauges – (refrigerant)
• Tachometer
• Thermometer
• Incline manometer or equivalent

Start-Up Procedure

The unit will be in operational mode during start-up. Use
necessary precautions to avoid injury. All data must be
collected while the unit is running.
 Make sure Pre-Start-Up checklist is complete.
 Jumper R to G, R to Y1, and R to Y2 (if applicable)
on the control board.
 Turn the disconnect on. After 3 minutes compressors
will come on. Make sure all fans and compressors
are rotating the correct direction.
 Allow the unit to run until the refrigerant system
stabilizes. Approximately 1-2 minutes.

Voltage Imbalance

In a 3-phase system, excessive voltage imbalance
between phases will cause motors to overheat and
eventually fail. Maximum allowable imbalance is 2%.
To determine voltage imbalance, use recorded voltage
measurements in this formula.
Key:
V1, V2, V3 = line voltages as measured
VA (average) = (V1 + V2 + V3) / 3
VD = Line voltage (V1, V2 or V3) that
deviates farthest from average (VA)
Formula:
% Voltage Imbalance = [100 x (VA-VD)] /VA

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