750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
8-23
8.19 — Air Pump and Lubricating System
Shim stock of appropriate thickness and area is then used under either the feet of the pump or the motor to estab-
lish parallel alignment. A tolerance of .008” is a permissible limit.
FIGURE 8-9. Coupling Alignment
After parallel alignment is established, check for angular alignment, which is done by checking the gap between the
coupling halves. The coupling should have a minimum gap of 1/16” and a maximum of 3/32”.
Set the spacing between the halves at one point by using a thickness gauge and then rotate the coupling slowly to be
sure that clearance at that point remains the same through 360 degrees of rotation. Adjust to obtain proper gap by
loosening the hold-down bolts and shifting either the pump or the motor as required. Generally, a slight tapping on
either the front or rear legs is all that is needed to obtain lateral adjustment. Rear legs may require shimming for ver-
tical correction.
Tighten the hold-down bolts after adjustments are made and recheck alignment.
Calipers can also be used to check angular alignment. Measure the overall distance of the outer ends of the coupling
halves at 90º intervals. Shift the pump or motor, as required, so that the ends of the coupling are the same distance
apart at all points. The coupling will then have proper angular alignment.
Remember that alignment in one direction may alter alignment in another. Recheck both angular and parallel align-
ment procedures after making any alteration.
A properly aligned coupling will last longer and will provide trouble free mechanical operation.
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