Micropump GN Series Installation, Operation and Warranty Information - Manual (Page 19)

19
DOC No: 7046 REV G
Fault Isolation
If the pump does not meet its design performance or fails to operate correctly, refer to the
following tables for assistance in identifying the cause and remedy:
PUMP PRODUCES NO LIQUID AT STARTUP
Cause Remedy
Inlet valve closed.
Discharge valve closed. Open inlet valve.
Open discharge valve.
Pump does not reach speed.
Magnets decouple. Check motor is running.
Open inlet & outlet valves.
PUMP SEIZES IMMEDIATELY AT STARTUP
Cause Remedy
Solids present in pump. Clean pump, tank, and piping system.
Replace any damaged parts before assembly.
PUMP DOES NOT ACHIEVE RATED FLOW OR PRESSURE AT STARTUP
Cause Remedy
Inlet valve not fully open. Open inlet valve fully.
Inlet filter or strainer is blocked. Clean inlet filter or strainer.
Internal Bypass adjusted incorrectly. Adjust internal bypass.
Pump rotates in wrong direction. Check motor electrical connections (refer to connection details supplied with
motor.)
Pump is drawing air. Check that inlet piping and fittings are air-tight.
Fluid viscosity too thick. Contact your local Micropump distributor or contact Micropump directly.
Differential head of the system is higher than
specified. Reduce differential head or contact your local Micropump distributor or
contact Micropump directly.
Pump cavitates, NPSH available is less than
NPSH required. Increase NPSH available.
MOTOR IS OVERLOADED
Cause Remedy
Differential head of the pump is higher than
desired. If pump capacity is greater than required, install additional bypass line from
discharge to inlet.
Discharge valve is fully open, pump operates
with reduced capacity and increased power
consumption. Adjust the capacity and differential head with a throttle valve in the bypass
line.
Fluid density too high or viscosity too thick. Contact your local Micropump distributor or contact Micropump directly.
PUMP PRODUCES NO LIFT OR DOES NOT SELF-PRIME
Cause Remedy
Pump is drawing air. Check that inlet piping and fittings are air-tight.
Fluid viscosity is too thin or too thick, pump
loses self-prime ability. Install foot valve at bottom of the inlet line, fill inlet- line and pump with liquid
before restart. Modify pipe layout.
Magnet coupling out of alignment. Signs of
rubbing may be present on the magnet cup. Check alignment. Ensure adapter/mount is of the correct type and is not dam-
aged or distorted. Use only Micropump adapter/mounts.
Mounting base not rigid. Ensure the base is adequately supported, particularly in the area of the motor
attaching points. Ensure attachment bolts are of the correct size and tighten
sufficiently.
Pump cavitates, NPSH available is less than
NPSH required. Increase NPSH available.