Porter Cable JOB BOSS C3550 Manuel D'instructions page 24

PROBLEM
Knocking Noise. Possible defect in safety
Squealing
sound.
D28914
CAUSE
valve.
Defective check valve.
Compressor mounting
screws loose
Carbon build-up in pump
Compressor pump has no
oil.
Operate safety valve manually
by pulling on ring. If valve still
leaks, it should be replaced.
Remove and clean, or replace.
Tighten mounting screws,see
Parts manual for torque
specifications.
Have checked by a Trained
Service Technician.
See Oil-Checking paragraph in
the Maintenance section.
24- ENG
CORRECTION