Pump Controllers - Grundfos DPK Series Installation And Operating Instructions Manual

5.4 Pump controllers

5.4.1 Level controllers
The liquid level can be controlled by the Grundfos LC
level controllers.
Suitable level controllers, depending on the size of
pumps:
• LC 231: a compact solution with certified motor
protection for a nominal current of up to 12A (9.6A
in the US) when running a single pump, or up to
9A (7.6A in the US) when running two pumps
simultaneously. Supports the DOL starting
method.
LC 231 supports analog level transmitters, digital
float switches and combinations of both. Air bells
are available as an accessory.
• LC 241: a cabinet solution offering modularity and
customisation for single- and dual-pump
versions. Supports DOL, star-delta and soft starter
starting methods. Standard variant ranges are
available for up to 23A in DOL, 43A in star-delta,
and up to 72A with soft starter. Customable
variants are available on request.
LC 241 supports analog level transmitters, digital
float switches and combinations of both.
Electrodes are available as an option and air bells
as an accessory.
"Level switches" can be air bells, float switches or
electrodes depending on the selected pump
controller.
Depending on the security levels and the number of
pumps, level switches can be used in the following
setups:
S1
S3
Pump operating levels, analog level transmitter and high-level float switch or digital float switches
• dry run (optional)
• stop
• start pump 1 (single-pump version)
• start pump 2 (dual-pump version)
• high level (optional).
Analogue level transmitters can be used, and all
levels can be customised. Level switches can be
used with level transmitters, for dry-run protection and
high level alarm.
The pump must not run dry. Install an
additional level switch to ensure that the
pump is stopped in case the stop level
switch is not operating.
Both controllers can be fitted with a single level
transmitter, and can be supported with one or two
digital float switches for high level and dry-run setup
for security. The controllers can also be equipped
with up to 5 pieces of digital float switches only in a
two-pump installation.
If a simple installation is required, a one-pump
installation can be controlled by just one digital float
switch acting as "start pump 1 / stop" where the one
float switch starts and stops the pump. A stop delay
can be added to avoid too many starts and stops.
Similarly a two-pump installation can be created with
two digital float switches.
FS
SR
S
LT
S1
S3
15