Troubleshooting - Goulds Pumps 3935 Installation, Operation And Maintenance Instructions

Troubleshooting

Troubleshooting
Problem
A. No Liquid delivered, not enough liquid delivered,
or not enough pressure
B. Pump works a while then quits
C. Pump takes too much power
D. Pump is noisy or vibrates
E. Pump leaks excessively at seal housing
F. High bearing temperature
Causes and corrective measures
1. Pump not primed or properly vented: check that casing and suction pipe are completely
2. Speed too low: check whether or not motor wiring is correct and receives full voltage, or
3. System discharge head too high: check system head (particularly friction losses).
4. Suction lift too high: check NPSH available (suction piping too small or too long may cause
5. Pump or piping obstructed: check for obstructions.
6. Wrong direction of rotation: check rotation.
7. Air pocket or leak in suction line: check suction piping for air pockets and/or air leaks.
8. Incorrect or damaged seal allowing leakage of air into pump casing or liquid leakage out:
9. Not enough suction head for hot or volatile liquids: increase suction head, consult factory.
10. Foot valve too small: install correct size foot valve.
11. Foot valve or suction pipe not immersed deep enough: consult factory for proper depth.
12. Entrained air or gases in liquid: consult factory.
13. Impeller clearance too great: check for proper clearance.
14. Impeller damaged: inspect and replace as required.
15. Rotating parts bind: check internal wearing parts for clearances.
16. Coupling or pump and driver misaligned: check alignment and realign if required.
17. Improper pressure gauge location: check correct position and discharge nozzle or pipe.
18. Head lower than rating: pumps too much liquid-consult factory. Install throttle valve.
19. Liquid heavier than anticipated: check specific gravity and viscosity.
20. Cavitation: increase NPSH available. Consult factory.
21. Improper bearing lubrication or bearings worn out: inspect and replace as required.
22. Internal recirculation due to damaged diffusers or diffuser O-rings: Replace damaged
23. Diffusers spinning due to insufficient torque on discharge head: Replace damaged diffusers
24. Pump not properly secured to base or piping not properly supported: provide for secure
25. Incorrect bearing frame oil level (high or low) or lack of grease: follow lubrication
22
filled with liquid.
turbine receives full steam pressure.
excessive friction losses). Check with vacuum or compound gauge.
inspect seal or replace as required.
Use baffle to eliminate vortices.
diffusers and 0-rings.
and reassemble with proper torque on discharge head.
bolting to base, proper base structure and support of pipes.
instructions.
Possible causes and correction
1, 2. 3. 4, 5, 6, 7. 8, 9, 10, 11, 12, 13, 14, 17, 22, 23
4,5, 7, 8, 9, 11. 12, 22, 23
15, 18, 19
15, 16,20,21,23,24
8
23,24,25
Model 3935 Installation, Operation and Maintenance Instructions