Wilo COE-2 MHIL, Installation And Operating Instructions Manual

Page: 27 / 100

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Installation and operating instructions Wilo-COE-2 MHIL 27
.
Faults Causes Remedies
1 or 2 pumps are not starting Air intake during suction Check the impermeability of all connections in the
suction pipework.
Check that the suction strainer for the reservoir is
properly submerged in water.
Foot valve suction strainer in
the reservoir is permeable or
obstructed Check the impermeability of the valve and replace
it if necessary.
Significant friction losses on the
suction side Calculate the friction losses and make sure that
they are compatible with the NPSH for the pumps.
Municipal water supply pressure
too low or 0 If the issue persists, it is important to use a reservoir.
Negative suction head over
reservoir too great Ensure that the minimum level of the reservoir
is compatible with the NPSH for the pumps.
Suction pipework obstructed
or valve on suction manifold
closed Check that the valve is open and clean pipework
if necessary.
The pumps are turning in the
wrong direction (three-phase) Cross-wire 2 power supply wires on the motor
terminals.