Fault Finding The Product - Grundfos DUOLIFT Series Installation And Operating Instructions Manual

11. Fault finding the product

WARNING
Toxic material
• Death or serious personal injury
• Wear protective gloves, close the
isolating valves and drain the tank
before you start any work on the tank.
Fault
1. The pump does
not start.
2. The pump does
not stop.
3. The pump starts
and stops
accidentally.
4. The tank is
emptying??
although the
pump is running.
5. The pump makes
an unusual sound.
Cause
a) The float switch is blocked in low
position.
b) The pump cable is defective.
a) The float switch is blocked in high
position.
a) The float switch is not set properly.
b) The level sensor tube is not fixed
properly in the tank and is moving up
as the liquid rises. The sensor receives
wrong signals.
c) The float switch cannot move freely
because the pump has moved.
a) There is an air pocket in the pump
impeller. The pump cannot build up
pressure.
a) The pump is blocked.
For faults indicated by alarms and related to the
controller, see the installation and operating
instructions for the controller.
For faults related to the pumps, see the installation
and operating instructions for the pumps.
Remedy
1. Make sure that the float switch can
move freely.
2. It may be necessary to adjust the
cable length. See section
6.1 Setting the start levels.
Repair or replace the cable.
1. Make sure that the float switch can
move freely.
2. It may be necessary to adjust the
cable length. See section
6.1 Setting the start levels.
Adjust the cable length of the float
switch. See section 6.1 Setting the
start levels.
Fix the tube to the tank. See fig. 11.
Position the pump according to fig. 7
or 8.
1. Drill a hole of maximum 6 mm in
the connecting pipes inside the
tank. The air is pushed out when
the pump starts, and the pump
builds up pressure. The pressure
loss due to the hole is negligible.
2. Do not drill a hole in the discharge
pipe outside the tank.
Take the pump out of the tank and
remove the blockage. You may need
to dismantle the pump. See the
installation and operating instructions
for the pump.
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