Applicable Systems
KSB Centrifugal Pump
Symptoms
The KSB pump displays alarm K007, indicating insufficient Net Positive Suction Head available. The pump is operating in cavitation, causing noise, vibration, and rapid impeller damage.
Possible Causes
- Suction lift too high or liquid level in supply tank too low
- Suction piping undersized or has excessive fittings and valves
- Liquid temperature elevated, reducing vapor pressure margin
Troubleshooting Steps
- Step 1: Calculate NPSHa and compare to NPSHr at the operating flow
NPSHa exceeds NPSHr by at least 1.0 meter of safety margin - Step 2: Inspect suction piping for restrictions, valves, or undersizing
Suction pipe diameter meets or exceeds pump inlet size with minimal fittings - Step 3: Check liquid temperature at the pump suction
Temperature is within the design range and vapor pressure margin is adequate
How to Reset
To reset: 1) Raise the liquid level or reduce suction lift. 2) Enlarge suction piping if undersized. 3) Cool the liquid if temperature is excessive. 4) Restart after verifying adequate NPSH margin.
Source: KSB Pump Operating Instructions, KSB SE & Co. KGaA
Category: Pump