Central Pneumatic 67853, Manual

Page 14

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Item 67853

Troubleshooting

Problem

Possible Causes

Likely Solutions

Engine will 

not start

(Note: See engine 

manual for engine 

specific issues.)

COMPRESSOR SPECIFIC:
1.  Pilot Valve closed. 

2.  Tank already pressurized.

COMPRESSOR SPECIFIC: 
1.  Open pilot valve before start procedure, close after unit is 

running.

2.  Turn engine on. Compressor will turn on as needed when 

pressure reaches preset level.

Compressor 

overheats

1.  Incorrect lubrication or not 

enough lubrication.

2.  Worn parts. 

1.  Lubricate using recommended oil or grease according to 

directions.

2.  Have qualified technician inspect internal mechanism and 

replace parts as needed.

Severe air 

leakage

1.  Poor air outlet seal.
2.  Loose cylinder/cylinder head. 

3.  Damaged valve or housing.
4.  Dirty, worn or damaged valve.

1.  Tighten or re-attach using thread seal tape.
2.  Tighten cylinder/cylinder head assembly.  If cylinder/cylinder 

head cannot tighten properly, internal parts may be misaligned.

3.  Replace damaged components.
4.  Clean or replace valve assembly.

Unit stalls

1.  Low engine idle. 

2.  Severely clogged air filter.
3.  Improper lubrication.
4.  Defective pilot/unloader valve.

1.  Qualified technician should increase idle to 2,200±100 RPM by 

adjusting pressure switch.

2.  Replace air filter.
3.  Check for proper oil level.
4.  Replace pilot valve.

Excessive noise

1.  Loose drive pulley or flywheel. 

2.  Misaligned pulleys.
3.  Lack of oil in crankcase.
4.  Worn connecting rod.
5.  Worn wrist pin bushing.
6.  Worn bearings.
7.  Loose belts.

1.  Loose pulleys are a common cause of “knocking”. Tighten 

appropriate bolts.

2.  Align pulleys with straightedge and secure in place.
3.  Check for proper oil level.
4.  Replace connecting rod.
5.  Remove piston assembly and replace necessary parts.
6.  Replace bearings and oil.
7.  Check for proper belt tension.

Oil in the 

discharge air

1.  Wrong type of oil or low-

quality oil.

2.  Overheating.
3.  Restricted intake air.
4.  Worn piston rings.
5.  Excessive moisture in the 

tank.

1.  Change oil. Check oil recommendations under EQUIPMENT 

SET UP, Equipment Oil Fill section of this manual.

2.  See above Excessive Noise section.
3.  Clean or replace air filter.
4.  Replace piston rings.
5.  Drain moisture from the tank daily.

Low discharge 

pressure

1.  Air leaks. 

2.  Leaking valves. 

3.  Restricted air intake.
4.  Blown gaskets.
5.  Slipping belts.

1.  Listen for escaping air. Apply soap solution to all fittings and 

connections. Bubbles will appear at points of leakage. Tighten 

or replace leaking fittings or connections.

2.  Remove head and inspect for valve breakage, weak 

valves, scored valve plate, etc. Replace defective parts and 

reassemble. Replace head gasket each time the head is 

removed.

3.  Clean or replace air filter element.
4.  Replace and gaskets proven faulty on inspection.
5.  Tighten Belts (See monthly maintenance.)

Follow all safety precautions whenever diagnosing or servicing the equipment or engine.