19
Example 3: Falling barometric pressure
If the barometric pressure falls after the pump has
stopped, the pump will register this fall as a fall in
liquid level. The result may be that the pump starts
after the set start level was reached. See fig. 10.
Therefore, the distance between the pump stop level
and the inlet to the tank should be at least 50 cm.
See fig. 7.
Fig. 10
Example 3: Falling barometric pressure
10.4 Thermal switches
All pumps have two sets of thermal switches
incorporated in the stator windings.
11. Start-up
After one week of operation after replacement of the
the shaft seal, the condition of the oil in the oil
chamber should be checked. See section
for procedure.
11.1 Before start-up
Proceed as follows:
1. Remove the fuses. Check that the impeller can
rotate freely. Turn the impeller by hand.
2. Check the condition of the oil in the oil chamber.
See also section
3. Check that the level sensor is clean, and that the
protective cap is intact.
4. Check that the dry-running sensors are clean.
5. Open the isolating valves, if fitted.
6. Lower the pump into the liquid, and insert the
fuses.
7. Check that the system has been filled with liquid
and vented. The pump is self-venting.
8. Switch on the power supply to the pump.
When powered, the pump will start and pump down
to the dry-running level. This function can be used to
check the pump.
TM
04
43
39
12
09
Warning
The pump incorporates dry-running
protection based on two dry-running
sensors placed on either side of the
unit. If a dry-running sensor detects
water shortage, the pump will stop
immediately and cannot restart until the
sensors are fully submerged again.
The sensors must be cleaned at regular
intervals, depending on the deposits of
sludge on the sensors in the tank.
Note
When a thermal switch is activated,
the pump will stop immediately and will
not restart until the motor windings
have cooled sufficiently.
If the pump does not restart
automatically, the pump must be reset
and restarted manually. See section
11.4 Resetting the pump.
If the pump has to be restarted
manually repeatedly, contact Grundfos
or an authorised service workshop.
Barometric pressure
Pump runn
ing
Pum
p
running
Pump runni
ng
Start level set
Stop level
Warning
Before starting work on the pump,
make sure that the fuses have been
removed or the mains switch has been
switched off. It must be ensured that
the power supply cannot be
accidentally switched on.
Make sure that all protective equipment
has been connected correctly.
The pump must not run dry.
Warning
Opening the clamp when the pump is
started can lead to personal injury or
death.
Warning
The pump must not be started if a
potentially explosive atmosphere is
present in the tank.
Caution
In case of abnormal noise or vibrations
from the pump or other pump or supply
failure, stop the pump immediately.
Do not attempt to restart the pump until
the cause of the fault has been found
and the fault corrected.
Note
If the dry-running sensors are not
covered by liquid, the pump cannot
start.
