Section 5: TROUBLESHOOTING
5.10 VACUUM
PROBLEMS
Welch dry vacuum pumps are 100% oil-free. The pump employs a non-lube piston and
cylinder. Leakage, contamination and unusual outgassing are the general causes of problems
with poor vacuum. To operate at maximum effi ciency a system must be thoroughly clean. If
the system is completely clean and free from leaks, and unwarranted vacuum problems still
exist, the pump should be checked. A simple criterion for the condition of the pump is the
determination of its maximum vacuum capability. This can be accomplished by blocking of the
intake and reading the vacuum level on the gauge (See Section 2.8).
5.20 TROUBLESHOOTING
TABLE
Poor
Pumping
Speed
Poor
Vacuum
Loud
Unit
Possible Cause
Corrective Action
X
X
X
Damaged valves
Replace fl apper valves
X
X
X
Debris in valves
Remove debris and check for valve damage
X
X
X
Damaged gasket
Replace gasket
X
X
X
Loose head screw
Tighten head screw
X
X
X
Loose fi tting
Tighten fi tting
10
