Troubleshooting

At start-up

1. Check pump rotation is correct (2-3 seconds)
2. Check flushing liquid to seal or gland is available at the pump
3. Check for alignment and a dust free coupling

Specific issues:

1. No liquid delivered:

1. Pump not primed
2. Suction lift too high. Check with a gauge at the pump suction
3. Wrong direction of rotation
4. Pump not rotating (failure of drive from prime mover)
5. Suction & Delivery pipes connected on wrong sides of pump

2. Not enough liquid delivered:

1. Air leaks in suction or through stuffing box
2. Speed too low
3. Suction lift too high, or not enough suction head (for hot liquids)
4. Foot valve too small or obstructed
5. Foot valve or end of suction pipe not immersed deeply enough
6. Piping improperly installed permitting air or gas to pocket in pump
7. Mechanical defects: Pump damaged Pump badly worn Packing defective
8. Relief valve not seating or jammed by foreign matter
9. Relief valve set for too low a pressure

3. Pump works for a while then loses suction:

1. Leaky suction lines
2. Suction lift too high
3. Air or gases in the liquid

4. Pump takes too much power:

1. Speed too high
2. Liquid heavier or more viscous than we quoted for
3. Suction or discharge line obstructed
4. Mechanical defects: Shaft bent; rotating element binds; stuffing boxes too tight; misalignment due to improper connection of pipe lines or driver
5. Check pressure is being measured at the pump and not some distance away from the pump thus ignoring pressure losses in piping, valves, etc
6. Discharge pressure higher than quoted for

5. Noisy pump:

1. Speed too high
2. Suction lift or viscosity too high (piping diameter too small) preventing filling of gear tooth spaces (c) Wrong direction of rotation (Note: recesses in the pump covers to prevent hydraulic noise operate only in one direction)
3. Badly supported pipes or bedplates causing resonant vibration. Rubber mounting can help.
4. Relief valve chattering
5. Pressure too low: an increase in pressure can prevent gear noise in low pressure applications
6. Worn pump, check for wear

6. Excessive Gland leakage:

1. Packing hard and shafts scored
2. Pressure on pump too high or pressure relief passage blocked
3. Shaft run out excessive
4. When repacking a gland all the old packing must be removed. It is not good enough just to add extra rings as the original packing becomes compressed

7. Excessive wear:

1. Abrasive liquid / Contaminated liquid
2. Excessive speed
3. Misalignment
4. Excessive loading on drive shaft, axial or radial
5. Pump is running dry
6. Viscosity less than stated

8. Motor running hot and overheating:

1. Back pressure too great
2. Incorrect supply voltage
3. Motor phasing
4. Pump operating outside temperature range
5. Air temperature too high
6. Motor covered in dust
7. (g) Electrical connections not correct for starting method
8. (h) Natural ventilation blocked

9. Pump overheating:

1. Re-circulating small amount of liquid
2. Over tight gland
3. Running dry
4. Pump out of alignment