The Pump Runs Constantly Or Gives Too Little Water; The Pump Runs But Gives No Water - Grundfos UNILIFT APG Installation And Operating Instructions Manual

9.3 The pump runs constantly or gives too little water

Cause
The pump is partly blocked by impurities.
The outlet pipe or valve is partly blocked by
impurities.
The impeller is not properly fixed to the shaft.
Incorrect direction of rotation.
Incorrect setting of the float switch.
The pump is too small for the application.
The impeller is worn.
Related information
6.1 Checking the direction of rotation

9.4 The pump runs but gives no water

Cause
The pump is blocked by impurities.
The outlet pipe or valve is blocked by impurities.
The impeller is not properly fixed to the shaft.
There is air in the pump.
The liquid level is too low. The pump inlet is not
completely submerged in the pumped liquid.
Pumps with float switch: The float switch does not
move freely.
Related information
5.6 Adjustment of the float switch cable length
Remedy
Clean the pump.
Clean the outlet pipe or valve.
Tighten the impeller.
Reverse the direction of rotation.
Adjust the float switch.
Replace the pump.
Replace the impeller.
Remedy
Clean the pump.
Clean the outlet pipe or valve.
Tighten the impeller.
Vent the pump and the outlet pipe.
Submerge the pump in the liquid or adjust the float
switch.
Adjust the float switch.
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