Problems: Causes And Remedies; Appendix; Permissible Pump Pressure - Andritz SD 39 Série Instructions De Service

Series SD 39

6. Problems: Causes and Remedies

1) Output low or no output at all
2) Excessive output
3) Motor overload and thermistor stops
4) Pressure surge or water hammer on shut down
1) 2) 3) 4) Problem
Excessive draw-down in sump, excessive
suction lift or inadequate flooded suction
Pump not completely primed
Air lock in suction pipe
Excessive delivery pressure
Insufficient delivery pressure
Wrong rotation
Pipework, fittings or pump clogged
Pump internal worn
Speed too low
Speed too high
Motor two phasing
Set misaligned
Packed gland packing overtightened
Excessive viscosity/density of pumped medium
System design

7. Appendix

7.1

Permissible pump pressure

Type
SD 200-250
SD 250-300
SD 300-310
SD 350-420
SD 400-460
SD 500-600
SD 510-630
* The maximum permitted final pump pressure [bar] consists of the intake pressure and the pump delivery head at zero capacity.
26
Remedy
• Check the system design and pipe sizing
• Check the settings and operation of level controls
• Vent the pump
• Check shaft sealing arrangements for air tightness
• Prime the suction pipe
• Check suction pipework and valves for air tightness
• Open up restricting valves
• Check system design for excessive pressure losses
• Modify pump (after consulting the manufacturer)
• Check the system design
• Restrict discharge valve
• Correct rotation
• Remove deposits or obstructions
• Replace worn parts
• Check electrical installation
• Check electrical installation
• Check electrical installation
• Check alignment
• Eliminate loads from pipework and realign set
• Slacken gland packing
• Fit a more powerful motor (after consulting the manufacturer)
• Examine system design
Maximum admissible final pump pressure* [bar]
pump media temperature up to +80°C
casing parts made of
EN-GJL-250
7
7
5
7
5
5
5
Table 3: Problems
CuSn10-C
5
5
4
6
4
4
4
Table 4: final pressure of pump