Start-Up; Pump Operating Range; Shutdown - KSB RDLO Series Operating Instructions Manual

pump cannot reach its duty point; vibrations and
overheating will be the consequence. The pump set
or the shaft seal might be damaged.
Correct Direction of Rotation
The direction of rotation must correspond to the
direction indicated by the arrow on the pump. This
can be verified by switching the pump on and then
off again immediately.
Before checking the direction of rotation
make sure that there is no foreign matter in the
pump casing.
Never put your hands or any other objects into
the pump !
6.4.2

Start-up

Dry-running
Caution
increased wear and must be
avoided.
If no non-return valve is fitted on the discharge side,
close the discharge gate valve.
Fully open the suction-side shut-off element, if
installed.
All additional connections for cooling, heating,
lubrication, flushing or sealing liquid, etc., if
applicable, must be opened fully or switched on,
and the throughflow must be checked.
Switch on the motor.
As soon as the pump starts to deliver – that means
when the discharge pressure at the gauge rises -
slowly open the discharge gate valve fully.
The pump may be operated
Caution
against a closed discharge gate
valve only during the start-up and shutdown phase,
as otherwise impermissible temperature increases
occur, which lead to damage.
6.4.3

Pump Operating Range

The flow rate "Q" as a function of the discharge
head is achieved automatically in accordance with
the Q/H curve. The permissible pump operating
range is subject to limits having causes that are
independent of each other.
will result in
Page 10 of 24
1. Part-load operating limit at a low flow rate
This limit is indicated in the Q/H curve by Q
the continuation of the characteristic curve which is
not depicted.
It is not permitted to operate the
Caution
pump in the range from Q = 0 to
Q . Prolonged operation in this range causes
min
greatly increasing mechanical loads which the
components cannot
through the critical range, e.g. during start-up, is
permitted
2. NPSH-induced limits in the part-load and
overload ranges
These two limits are based on the ratio of
NPSH to NPSH
required available
as follows:
The intersections of NPSH
are projected to the Q/H curve, where they produce
the operating limits (refer to the diagram). Checking
of the NPSH-induced operating limit is not
necessary for operating the pump under design
conditions. If system-induced changes occur, an
NPSH check must be carried out. If necessary,
consult KSB's nearest customer service centre.
6.4.4

Shutdown

Close the shut-off element in the discharge line. If
the discharge line is equipped with a check valve,
the shut-off element may remain open, provided
there is back pressure in the line.
The shut-off element in the suction line must
not be closed when switching off the pump. Switch
off the motor, making sure that the unit runs
smoothly down to a standstill. In the case of
prolonged shutdown, the shut-off element in the
suction line has to be closed.
RDLO
required
available
or by
min
withstand. Brief passing
. They are determined
and NPSH
required available