SIMPLE TROUBLESHOOTING OF MECHANICAL VACUUM PUMPS

CONDITION

PROBABLE CAUSE

RECOMMENDED CORRECTIVE ACTION

Pump will not start.    Power Off   Check switches and fuses Belt/Pulley or coupling damaged. Pulley or coupling setscrew loose.   Check v-belt/pulley or coupling. Room is too cold   Drain and refill pump w/warm fluid. Try to start w/intake open to atmosphere Pump mechanism is seized   Pump to be repaired Pump does not reach Ultimate pressure      Pump oil is contaminated   Flush and change pump oil. Use a foreline trap and/or pas ballast valve in future Pump is not filled w/oil, or has low oil level   Add recommended pump oil. Pump has wrong oil in it.   Flush & refill w/ recommended oil Leak in vacuum system.   Locate & eliminate leak source Dirty foreline trap.   Clean out cold traps & replacement elements in coaxial and molecular sieve traps. Gas ballast valve open   Close valve if condensable vapors are not a problem. Excessively noisy pump     Intake or exhaust lines are restricted.   Clear and straighten out lines V-belt or coupling damaged.   Examine v-belt or coupling and replace. Slapping noise at ultimate pressure is typical for some pumps   Gas ballast slightly open will eliminate this noise. Inside mechanism damaged.   Pump to be repaired. Pump generates excessive smoke or oil mist from exhaust port   Pump overfilled with oil.   Drain excess pump oil. Pump operating continuously above its maximum operating pressure.   Use larger capacity pump or modify your vacuum system. Gas ballast valve wide open.   Close valve or install a heavy duty exhaust filter Pump oil is unusual in Color – dark and dirty   Pump oil contaminated by process gases, dirt, or other foreign material ingested by pump.   Flush and change pump oil. Use a foreline trap and/or gas ballast valve in future. Consider using an oil filtration system or inert pump oils Pump oil has degraded.   Pump was run too low on oil. The recommended oil was not used. Pump is running continuously above its maximum operating pressure Gas ballast valve is plugged.   Clean gas ballast valve. Flush and change pump oil Pump does not achieve its rated pumping speed.    Pump is running too cold   Allow pump to run for al least an hour until it warms up to its operating temperature. Exhaust or intake line is too narrow   Install larger inner diameter tubing Pump oil is contaminated.   Flush and change pump oil. Use a foreline trap and/or gas ballast valve in future. Very dirty trap or intake line.   Clean out cold traps and replacement elements in coaxial and molecular sieve traps. Clean or replace vacuum piping. Pump is leaking oil severely Clogged exhaust line.   Disconnect pump from exhaust line and run or clean clog in exhaust line.