FORM 100.10-NOM2
35
YORK INTERNATIONAL
If any unusual vibration or noise oc-
curs, stop the unit immediately and
recheck all items.
If the vibration continues, the belts should be removed
from the drive and the motor be allowed to run un-
loaded to determine if the motor shaft is possibly bent,
if there are defective motor bearings, or if the motor is
unbalanced.
All units are dynamically balanced prior to shipment.
However, there are certain operating speeds at which
the natural frequency of the rotating member is attuned
to the natural frequency of certain panels or compo-
nents which are a part of the enclosure. These vibra-
tions can tend to reinforce each other in such a way
that excessive vibration can be encountered under cer-
tain conditions. It is difficult to predetermine this condi-
tion because it is affected by the mounting arrange-
ment, the various modules used in the makeup of the
assembly, and the duct work connections.
If the above check reveals no apparent discrepancies
and vibration is still present, the speed of the unit should
be lowered approximately 10 percent to determine if a
natural frequency is causing the vibration. If the unit
contains water coils, they should be filled with water
when the check is made.
Under no condition should the units be allowed to con-
tinue to operate when excessive unit vibration is appar-
ent. Permanent damage may result which will not be
covered under the warranty if the unit is allowed to
continue in operation when excessive vibrations are in
evidence.
After 24 hours of satisfactory opera-
tion, shut down the equipment and
check all foundation bolts, shaft bear-
ings, drive set screws and belt tension,
and tighten where required.
TEMPERATURE LIMITATIONS
Standard Motors (Class B Insulation) - 104°F
Motors with Class F Insulation - 140°F
Power Wiring - 140°F
Controls & Control Wiring - 140°F
Prefilters - 150°F
High Efficiency Filters - 200°F
Variable Speed Drives - 104°F
STATIC PRESSURE LIMITS
General classification of units low/medium/high static
pressure.
Low Pressure Package 0 - 3" I.W.G.
A. Cabinet construction: For static pressure up to 3"
I.W.G.
B. All access doors are double wall and open to the
outside with door latches, standard flat gasket and
standard SS hinges
Medium Pressure Package 3 - 6" I.W.G.
A. Cabinet construction: For static pressure up to 6"
I.W.G.
B. All access doors are double wall with bulb gaskets,
open in or out with door latches and full height
hinges.
High Pressure Package 6 - 9" I.W.G.
A. Cabinet construction: For static pressure up to 9"
I.W.G.
B. All access doors are double wall. Doors open with
full height hinges, door latches and seals.
FIG. 39 –
TYPES OF CENTRIFUGAL FAN
IMPELLERS
LD06350
3
