Trane QFNA-IOM-1 - Manual (Page 14)

Installation of Motor and
Beltguard When NOT
Factory Installed
Arrangements 1 and 9
Remove the discharge cone
covering the fan shaft. Check the
sheave bore for burrs and
lubricate for easier mounting. Do
not use excessive force when
mounting sheaves, as this may
damage the bearings. Be sure the
fan and motor shafts are parallel.
See Figure 9.
Set the motor sheave with a 1/2"
space between block-off retainer
and back of sheave as shown in
Figure 6. Align the sheaves with a
straight edge as in Figure 9 and
tighten the setscrews. When the
sheaves are not the same width,
place a string in the center groove
of both sheaves and pull tight. The
string should go straight through
the center of both grooves.
Move the motor in as close to the
fan shaft centerline as the
adjusting angles will permit.
Slip the belts over the sheaves
without forcing them. Forcing the
belts may cause damage.
Tighten the belts slightly and
manually rotate the drive several
times. As a check, on multiple belt
drives, determine that the force of
deflection is approximately the
same by pushing each belt in an
equal distance at a point halfway
between the sheaves.
After realignment, tighten the belts
to a reasonable tension. Operate
the unit a few minutes to allow
belts to seat (See Start-Up). Belts
should not slip when running, but
a slight squeal at startup is
normal. Do not over-tension belts.
Belt tension should be rechecked
after eight hours of operation and
monthly thereafter. When the belt
is in operation, the tight side of the
belt should form a straight line
from sheave to sheave with only a
slight bow on the slack side.
Attach the front side of the belt
guard to the rear panel assembly
already in place on the unit using
clips or screws provided. Keep the
polyurethane gasket in position
during this operation.
Replace the end cone using the
screws and/or clips originally
used. Be sure belts do not scrape
the edge of the cutout in the end
cone when the unit is in operation
Installation —Q Fan
14 FNA-IOM-1
Figure 9—Aligning Sheaves With A Straight Edge
For Sheaves Of The Same