valent VX Series - Start-Up Unit (Continued); Pre-Start-Up Checklist; Start-Up Procedure Steps; Voltage Imbalance Calculation

Dedicated Outdoor Air Unit 23
Pre-Start-Up Checklist
o Remove any foreign objects that are located in the
unit.
o Check all fasteners, set-screws, and locking collars
on the fans, bearings, drives, motor bases and
accessories for tightness.
o Rotate the fan wheels and energy recovery wheels
by hand and ensure no parts are rubbing.
o Verify diameter seal settings on the energy recovery
wheel.
o Filters can load up with dirt during building
construction. Replace any dirty pleated filters and
clean the aluminum mesh filters in the intake hood.
o Verify that non-motorized dampers open and close
properly.
o Check the tightness of all factory wiring
connections.
o Verify proper drain trap installation.
o 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.
o Look over the piping system.
o Inspect all coils within the unit. Fins may get
damaged in transit or during construction. Carefully
straighten fins with a fin comb.
Electrical
oDisconnect and lock-out all power switches.
o Verify control wire gauge.
o All field-mounted sensors and instruments are
installed and wired.
o Unit controls are off.
o Electrical service matches unit voltage.
o Electrical field wiring is complete.
o All electrical connections are tightened.
o Compressor and motor breakers or fuses are open
(disabled).
o Main power is wired to the disconnect.
o Discharge air sensor is installed per wiring
instructions.
o Space temperature and humidity sensors are
installed per if selected with unit.
Compressors
o This unit contains an external crankcase heater for
each standard or digital scroll compressor. The
variable speed compressor uses internal stator
heating. Each compressor 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.
oCompressor shipping brackets are removed if
provided.
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.
o Make sure Pre-Start-Up checklist is complete.
o Jumper R to G, R to Y1, and R to Y2 (if applicable)
on the control board.
o Turn the disconnect on. After 3 minutes compressors
will come on. Make sure all fans and compressors
are rotating the correct direction.
o 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
Start-Up Unit
IG Furnace
o If there is an indirect gas-fired furnace in this unit,
refer to the manual provided with this unit for Pre-
Start-Up information.
o Gas piping is complete and gas lines are purged.
o Gas venting is in place.
Hot Water/Chilled Water Coils
o Chilled water piping system is complete.
o Hot water piping system is complete.
o Control valves are installed, wired, and operating
properly.
o Water coils are balanced to design GPM.
o Water system is free of air.