Ingersoll-Rand 77H Series, Maintenance Information

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Troubleshooting Guide
Trouble Probable Cause Solution
Low power or low free speed Low air pressure at the Inlet Check the air pressure at the Inlet. The pressure must not
exceed 90 psig (6.2 bar/620 kPa).
Plugged Inlet Bushing Screen Clean the Screen in a clean, suitable, cleaning solution. If it
cannot be cleaned, replace it.
WARNING
Never operate a Grinder without an Inlet Screen.
Ingestion of dirt into the Grinder can, in some cases,
cause an unsafe condition.
Worn or broken Vanes Replace a complete set of new Vanes.
Worn or broken Cylinder Replace the Cylinder if it appears cracked or if the bore is
wavy or scored.
Improper lubrication or dirt
build-up in the motor
Lubricate the Grinder as instructed in
LUBRICATION . If lubrication does not result in satisfactory
operation, disassemble the motor, clean and inspect all
parts.
High free speed Worn Rear End Plate Assembly and/or
Controller Seal in Controller Assembly.
Replace the Rear End Plate Assembly and/or
Controller Assembly
Grinder will not run Coupling Nut too tight Loosen Coupling Nut and re-tighten to 50 to 52 ft-lb (68 to
70.5 Nm) torque.
WARNING
Do not exceed 52 ft-lb (70.5 Nm) torque
Rough operation Worn or broken Rear Rotor Bearing or Front
Rotor Bearing
Examine each bearing. Replace if worn or damaged.
Bent Arbor Mount the Arbor on centers. Check bearing
diameter runout with an indicator. Replace the Arbor if
runout exceeds 0.002” (0.051 mm) Total Indicator Reading.
Scoring Improper assembly Make certain that all motor parts are properly aligned
prior to clamping the Motor Assembly.
Air leaks Worn Valve Seat or Valve Seat Washer Replace worn parts.
Worn Throttle Valve Seals Replace both Seals.
Oil Chamber Plug and Oiler Plug Washer
not tight
Tighten the Plug. If the problem persists, replace the Plug.
Excessive runout (exceeds TIR at
a point one inch from the end
of the Collet)
Check for worn or damaged Collet. Examine
the Front Rotor Bearing for wear, damage or
excessive play.
Replace the Collet and Collet Nut. Replace the Front Rotor
Bearing.
Related Documentation
For additional information refer to:
Product Safety Information Manual 04584959.
Product Information Manual 16573214 and 16576100.
Parts Information Manual 16573271.
Manuals can be downloaded from ingersollrandproducts.com