Excell Precision E7540 User Manual
Page 25

25-ENG
A18791
PROBLEM
CAUSE
CORRECTION
Knocking Noise. Possible defect in safety
valve.
Operate safety valve manually 
by pulling on ring. If valve still 
leaks, it should be replaced.
Loose pulley.
Tighten pulley set screw, see 
Parts manual for torque speci-
fications.
Compressor mounting 
screws loose.
Tighten mounting screws,see 
Parts manual for torque speci-
fications.
Loose flywheel.
Tighten flywheel screw, see 
Parts manual for torque speci-
fications.
Loose belt.
Check belt tension, see "Ad-
justing Belt Tension" in the 
Maintenance section.
Carbon build-up in pump.
Have checked by a Trained 
Service Technician.
Belt to tight.
Check belt tension, see "Ad-
justing Belt Tension" in the 
Maintenance section.
Excessive belt 
wear.
Loose belt.
Tight belt.
Loose pulley.
Have checked by a Trained 
Service Technician.
Pulley misalignment.
See "Motor Pulley/Flywheel 
Alignment" paragraph in the 
Maintenance section.
Squealing 
sound.
Loose belt.
Compressor pump has no 
oil.
See Oil-Checking paragraph in 
the Maintenance section.
Check belt tension, see "Ad-
justing Belt Tension" in the 
Maintenance section.
Check belt tension, see "Ad-
justing Belt Tension" in the 
Maintenance section.
Check belt tension, see "Ad-
justing Belt Tension" in the 
Maintenance section.
Defective check valve.
Remove and clean, or replace.
