Welch Vacuum 1376N Chemstar - Manual (Page 33)

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Part 9 Toubleshooting Your CHEMSTAR Pump
A. Poor Vacuum Reading
1. Disconnect vacuum pump from your vacuum system.
2. Obtain 1 gallon of DIRECTORR Gold Oil, 1 gallon or larger clear plastic container, clear drain hose (1/4 inch ID by at
least 2.5 feet long), rubber gloves, goggles, apron and pliers.
3. Carry out a forced oil fl ush if motor can turn pumping mechanism without excessive noise (See Section 6 B). If
pumping mechanism cannot be turned by motor, have pump sent into factory repair center.
4. Check ultimate vacuum with thermocouple gauge. (See Section 7 B. Step 8 for how to do this.) If reading is still
unsatisfactory, consult with Welch Technical Service after checking for leaks in your connections.
B. Noisy Pump
1. Locate noise source on your vacuum pump (motor, belt, pump).
2. If motor makes noise:
- Check for loose bolts on motor mount.
- Loose belt, tighten by loosing bolts on motor and moving motor away from pump until belt exhibits a ½ inch
defl ection.
4. If pump makes noise:
- Vanes may be sticking, carry out a forced oil fl ush (See Section 7 B.).
5. If noise level is still unsatisfactory, consult with WELCH Technical Service at 847-676-8800.
C. Excessive Oil Mist
1. Check oil level. Maintain the level between the two lines on the oil window during operation. Too high a level will
cause excessive oil mist.
2. Determine the vacuum level in your system with a thermocouple gauge or manometer. Be sure the pump is operating
at a pressure of 10 Torr or lower for continuous operation
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If not, discuss application with Welch Technical Service before proceeding to prevent oil from overheating and breaking
down resulting in the pump failing.
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3. A system leak(s) or degassing can cause excessive oil mist. Locate and seal the vacuum leaks. High vapor loads
may require a larger pump to compensate.
4. An oil mist eliminator can be installed for coalescing the oil mist from the exhaust gases. If an oil mist eliminator is
already installed, the element may need to be replaced if saturated with oil. Open up oil mist eliminator and examine the
element; replace if needed.
5. Check the oil condition for any visible change in color or consistency. Contaminants in the oil can add to the amount of
oil exhausted. Carry out a forced oil fl ush if contamination is discovered (See Section 6 B).