7
Cast Iron Series
STRAIGHTEDGE
FLYWHEEL
AIR COMPRESSOR
MOTOR
A
B
C
MOTOR
DRIVE
PULLEY
SETSCREW
Figure 9 - Top View
touching the rim on both sides of the
face. The belts should be parallel to this
straight edge (see Figure 9). Dimension
A should be the same as B and C to
ensure proper alignment of the belts.
Maintenance
(Con’t)
Slots in the bed-plate allow for sliding
the motor back and forth to adjust belt
tension.
STORAGE
If compressor is to be stored for a short
period of time, make sure that it is
stored in a normal position and in a
cool protected area.
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Troubleshooting Chart
Symptom
Possible Cause(s)
Corrective Action
1. Low voltage or no voltage
2. Shorted or open motor winding
3. Malfunctioning check valve or unloader valve
4. Malfunctioning pressure switch - contacts will not
close
1. Pressure switch set too high
2. Malfunctioning check valve
3. Incorrect fuse size or magnetic starter heaters
4. Malfunctioning motor
5. Loose Wiring
1. Loose pulley, flywheel, belt, belt guard, etc
2. Lack of oil in crankcase
3. Compressor floor mounting loose
4. Malfunctioning check valve
Water condensing in crankcase due to high humidi-
ty
1. Be sure there is a problem
2. Restricted air intake
3. Wrong oil viscosity
4. Worn piston rings
5. Oil leaks
6. Scored cylinder
1. Excessive water in tank
2. Hot, humid weather
Broken first stage inlet valve (two-stage unit)
Broken inlet valve (single stage unit)
1. Air demand too high
2. Leaks or restrictions in hoses or piping
3. Slipping belts
1. Worn check valve
2. Check all connections and fittings for tightness
3. Check tank for cracks or pin holes
1. Pulley out of alignment
2. Belts too tight or too loose
1. Dirty air filter
2. Blown cylinder head gasket
3. Worn/broken intake/discharge valves
4. Air leaks
Excessive water in tank
1. Wrong pressure switch setting
2. Malfunctioning ASME safety valve
3. Pressure switch contacts welded
Malfunctioning check valve
Malfunctioning unloader valve on pressure switch
1. Head gasket or the gasket in the valve plate
assembly blown
2. Valve not seating properly
3. Malfunctioning safety valve
Malfunctioning tank check valve
1. Check with voltmeter, check overload relay in magnetic starter or
reset switch on motor. If overload or reset switch trips repeatedly,
find and correct the cause. See next item
2. Replace motor
3. Replace check valve or unloader valve
4. Repair or replace pressure switch
1. Adjust or replace
2. Clean or replace faulty valve
3. Be sure that fuses and heaters are rated properly
4. Replace motor
5. Check all electrical connections
1. Tighten
2. Check for damage to bearings, replenish oil
3. Shim to level and tighten or place on islolator pads
4. Replace check valve
Pipe air intake to less humid air source. Run pump
continuously for one hour
1. Diagnose oil contamination problems by testing the discharge air or
measuring oil consumption from the crankcase
2. Clean or replace air filter
3. Drain oil. Refill with oil of proper viscosity
4. Replace rings
5. Tighten bolts, replace gaskets or o-rings
6. Replace cylinder
1. Drain tank
2. Purchase dryer
Replace valve assembly
1. Limit air usage
2. Check for leaks or restriction in hose or piping
3. Tighten belts
1. Replace check valve
Do not disassemble check valve
with air in tank
2. Tighten
3. Replace tank. Never repair a damaged tank
1. Realign motor pulley
2. Adjust tension
1. Clean or replace filter element
2. Install new gasket
3. Install new valve plate assembly
4. Tighten joints
Drain tank, check speed. See Performance table
1. Adjust to lower pressure (175 psi maximum for two-stage unit or 135
psi for single stage unit) (See Operation)
2. Replace ASME safety valve
3. Replace pressure switch
Replace the check valve if the unloader valve bleeds off constantly
Replace the pressure switch if the unit does not hiss for a short period
of time when the unit shuts off
1. Replace valve plate and gaskets
2. Replace valve plate and gaskets
3. Replace safety valve
Replace the check valve
Motor hums and runs slowly or
not at all
Reset mechanism cuts out
repeatedly or fuses blow
repeatedly
Excessive noise in operation
Milky oil in oil reservoir
Excessive oil consumption or oil
in air lines
Water in discharge air
Air blowing out of inlet
Insufficient pressure
Tank does not hold pressure
when compressor is off and
shutoff valve is closed
Excessive belt wear. (Light dust
from start is normal. Worn belts
separate at layers)
Tank pressure builds slowly
Tank pressure builds up quickly
on compressor
ASME safety valve pops open
while compressor is running
Pressure switch continuously
blows air out the unloader valve
Pressure switch unloader valve
does not release air when the
unit shuts off
Interstage safety valve pops off
while the unit is running
Interstage safety valve pops off
after the unit shuts off
