Setting A Pump To Run-On; Setting The Pump Start Delays; Reducing Wall Cling - Siemens SITRANS LUT400 Operating Instructions Manual

General Operation
7.7 Pump Control
7.7.6.2

Setting a pump to run-on

This functionality is used to reduce sludge and sediment from building up at the bottom of a
wet well, thereby reducing maintenance. This is achieved by running the pumps below the
normal OFF setpoint and requires you to set a run-on duration and interval to control this
event.
Example:
Pump 1 is set to pump for an extra 60 seconds every 5 hours, pump 2 should not run-on.
Parameter
Run-On Interval (2.7.2.3.2.)
(Page 193)
Run-On Duration Pump 1
(2.7.2.3.3.) (Page 193)
Run-On Duration Pump 2
(2.7.2.3.4.) (Page 193)
7.7.6.3

Setting the pump start delays

In the event that power to the SITRANS LUT400 has been lost, the pump start delay ensures
that all of the pumps do not start at once to avoid power surges. There are two parameters
used here: Pump Start Delay and Power Resumption Delay.
Example:
The delay between pumps is set to 20 seconds and the delay of the first pump is set to 60
seconds.
Parameter
Delay Between
Starts (2.7.2.4.1.)
(Page 194)
Power Resumption
Delay (2.7.2.4.2.)
(Page 194)
7.7.6.4

Reducing wall cling

Use the Wall Cling Reduction function to randomly alter the ON and OFF setpoints over a
range. This eliminates the ridge of material that builds up at the setpoint that can give false
echoes.
This setting may increase the number of days between trips to clean the wet well.
Enable Wall Cling Reduction by setting Enable (2.7.2.1.1) (Page 188) = Enabled. Then set
the range in Level Setpoint Variation (2.7.2.1.2) (Page 188). The pump ON and OFF
setpoints are randomly varied inside this range so the material level does not stop at the
same point each time.
Example:
114
Sample Value
5
60
0
Sample Value Description
20 Wait at least 20 seconds between pump starts.
60 Wait for 60 seconds when power is restored for the first
pump to activate.
Description
Five hours between pump run-on occurrences.
The pump will run-on for 60 seconds.
Pump 2 will never run-on.
Operating Instructions, 07/2019, A5E33329501-AC
SITRANS LUT400