Pump Performance Is Unstable; Pump Runs Backwards When Switched Off - Grundfos CMBE Montage- Und Betriebsanleitung

11.3 Pump performance is unstable

The pump performance is unstable. No lights on
Grundfos Eye.
Cause
The pump inlet pressure
is too low.
The inlet pipe is partly
blocked by impurities.
Leakage in
the inlet pipe.
Air in the inlet pipe or
the pump.
Remedy
• Check the inlet
conditions of the pump.
• Remove and clean
the inlet pipe.
• Remove and repair
the inlet pipe.
1. Vent the inlet pipe or
the pump.
2. Check the inlet
conditions of the pump.
11.4 Pump runs backwards when switched
off
The pump runs backwards when switched off. No
lights on Grundfos Eye.
Cause
Leakage in
the inlet pipe.
The non-return valve is
defective.
Remedy
• Remove and repair
the inlet pipe.
• Remove and clean,
repair or replace the
valve.
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