Welch Vacuum 8925 Direct Drive Rotary Vane Pump - Manual (Page 25)

25
7.02 Trouble Shooting Guide
Condition Probable Cause Recommended Corrective Action
1. Power off. 1. Check switches and fuses.
Pump 2. Coupling damaged or 2. Check coupling and set screw.
will not coupling set screw loose.
start 3. Room is too cold. 3. Drain and refill pump with warm oil.
4. Pump mechanism is seized. 4. Pump to be repaired.
1. Pump is contaminated. 1. Flush and change pump oil.
Use a foreline trap.
2. Pump is not filled with oil, 2. Add recommended pump oil.
Pump does not or has low oil level.
reach ultimate 3. Pump has wrong oil in it. 3. Flush and refill with recommended pump oil.
pressure 4. Leak in vacuum system. 4. Locate and eliminate leak source.
5. Dirty foreline trap. 5. Clean out cold traps and replace elements
in coaxial and molecular sieve traps.
6. Gas ballast open. 6. Close gas ballast.
1. Intake or exhaust lines 1. Clean and straighten out lines and
are restricted. check oil level.
Excessively 2. Coupling damaged. 2. Examine coupling / replace.
noisy 3. Slapping noise at ultimate 3. Clean orifice air passage.
pump pressure is typical for
some pumps.
4. Inside mechanism damaged. 4. Pump to be repaired.
Pump generates 1. Pump overfilled with oil. 1. Drain excess pump oil.
excessive smoke 2. Pump operating continously 2. Use larger capacity pump, or
or oil mist from above its maximum modify your vacuum system.
exhaust port operation pressure.
1. Pump oil contaminated by
1. Flush and change pump oil. Use foreline
process gases, or other trap in futher. Consider using a oil filtration
Pump oil is foreign material ingested system or inert pump oils.
dark, has an by pump.
unusual color, 2. Pump oil has degraded. 2. Pump has run too low on oil. The
or is dirty recommended oil was not used. Pump
is running continously above its maximum
operation pressure.
1. Pump is running too cold. 1. Allow pump to run until it warms up to
its operating temperature.
2. Exhaust or intake line 2. Install larger inner diameter tubing.
Pump does not its too narrow.
achieve its rated 3. Pump oil is contaminated. 3. Flush and change pump oil.
pumping speed Use a foreline trap in futher.
4. Very dirty trap or 4. Clean out cold traps and replace elements
intake line. in coaxial and molecular sieve traps.
Clean or replace vacuum piping.
Motor is 1. Voltage selection 1. Convert motor to be compatible with
excessively noisy is incorrect. electrical supply. See Section:
4.03 / 4.04 Changing voltage setting.