Start-Up Components; Fan; Supply Fan (Plenum Type); Fan Wheel Rotation Direction - LG GEN2 Series Installation And Operation Manual

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Start-Up Components

Fan

The fan should be checked for free rotation. If any
binding occurs, check for concealed damage and foreign
objects in the fan housing.
CAUTION
When operating conditions of the fan are to be
changed (speed, pressure, temperature, etc.), consult
manufacturer to determine if the unit can operate
safely at the new conditions.

Supply Fan (Plenum Type)

The unit contains one or two plenum supply fans located on
the end of the unit opposite the outdoor air intake and may
optionally have a relief air blower which is referred to as an
exhaust blower in this document. Efficient fan performance
can be maintained by having the correct offset.
Offset: Proper offset, or overlap, is adjusted by loosening
the wheel hub from the shaft and
moving the wheel to the desired position along the
The transition between the inlet cone
and the wheel should be as shown; there is a smooth feel
to the profile when moving
one component to the other.
Offset
Fan Size
(inches)
ER35C 5/32
ER45C 3/16
ER50C 13/64
ER56C 1/4
PDL-355 5/32
PRM-450 3/16
PRM-560 15/64
shaft.
Tolerance (inches)
± 1/32
± 1/32
± 1/32
± 1/32
± 1/32
± 1/32
± 1/32
Refer to the respective installation, Operation and
Maintenance Manual shipped with this unit for additional
start-up and maintenance information regarding the
plenum fan.

Fan Wheel Rotation Direction

Check for proper wheel rotation by momentarily
energizing the fan. Rotation is determined by viewing the
wheel from the drive side and should match the rotation
decal affixed to the fan housing.
If the wheel is rotating the wrong way, direction can be
reversed by interchanging any two of the three electrical
leads. Check for unusual noise, vibration or overheating
of the bearings. Refer to the Troubleshooting portion of
this manual if a problem develops.

Supply/Exhaust Fan

The optional exhaust fan is a direct-drive plenum type.
Fan speed is controlled by a VFD which, in turn, is
controlled by the microprocessor controller or by an
external signal. Motor speed will be set on the VFD
during the unit Test and Balance, but after that, the VFD
will not normally be changed. Always check the motor
amperage rating shown on the motor nameplate when
changing the fan RPM. All access doors must be
installed except the control center door.

Vibration

Excessive vibration may be experienced during
initial start-up. Left unchecked, excessive vibration can
cause a multitude of problems, including structural
and/or component failure. The most common sources of
vibration are listed.
Many of these conditions can be discovered by careful
observation. Refer to the Troubleshooting section of
this manual for corrective actions. If observation cannot
locate the source of vibration, a qualified technician
using vibration analysis equipment should be consulted.
Generally, fan vibration and noise is transmitted to other
parts of the building by the ductwork. To eliminate this
undesirable effect, the use of flexible connectors is
recommended.
Vibration Causes
Off axis or loose components
Drive component unbalance
Poor inlet / outlet conditions
Foundation stiffness