© 2016 Littelfuse Protection Relays & Controls

Protection Relays

Pump Controls and Liquid Level Controls

www.littelfuse.com/LLC5

Rev: 1-A-062116

Liquid Level Controls

Description

The LLC5 provides dual probe conductive liquid level control

in a convenient octal plug-in package. Models are available

for fixed fill or drain operation. Isolated, pulsed DC voltage

on the probes prevents electrolytic plating. Less than 1 mA

of current is used to sense the presence of conductive liquid

between the probes and common. On adjustable units, the

sensitivity adjustment eliminates false tripping caused by

floating debris and foaming agents.

Operation

Drain (Pump-Down Mode): When the liquid level rises

and touches the high level probe, the output relay and LED

energize and remain energized until the liquid level falls below

the low level probe. The output relay and LED de-energize and

remain de-energized until the liquid rises and touches the high

level probe.

Fill (Pump-Up Mode): When the liquid level falls below

the low level probe, the output relay and LED energize and

remain energized until the liquid level rises and touches the

high level probe. The output relay and LED de-energize and

remain de-energized until the liquid level again falls below the

low level probe.

Features & Benefits

FEATURES

BENEFITS

Unique Probe

Protection logic

Probes are protected from scale build up through

pulsed DC signal between the probes.

LED status indicatior

Visual indication of relay engagement in pump-up or

pump-down activity

Isolated 5A

SPDT contacts

Allows control of loads for AC voltage

Accessories

BZ1 Front Panel Mount Kit

Provides an easy method of through-the-panel

mounting of 8- or 11-pin plug-in timers, flashers,

and other controls.

NDS-8 Octal 8-pin Socket

8-pin 35mm DIN rail or surface mount. Rated

at 10A @ 300VAC. Surface mounted with two

#6 (M 3.5 x 0.6) screws or snaps onto a 35 mm

DIN rail. Uses PSC8 hold-down clips.

PSC8 Hold-down Clips

Securely mounts plug-in controls in any position.

Provides protection against vibration. Use with

NDS-8 Octal Socket. Sold in pairs.

Note: use of the PSC8 clips partley covers the LED window of

the LLC5 unit. Use of alternative socket base P1011-6 with its

corresponding hold down clips PSCRB8 do not cover up the LED

window, but the socket base is not DIN rail mountable.

Ordering Information

MODEL

LINE

VOLTAGE

DESCRIPTION

LLC52AA

24VAC

For Drain (pump-down) operation with

adjustable sense resistance

LLC52BA

24VAC

For Fill (pump-up) operation with adjustable

sense resistance

LLC54AA

120VAC

For Drain (pump-down) operation with

adjustable sense resistance

LLC54AAS

120VAC

For Drain (pump-down) operation with

adjustable sense resistance and reverse

connection (#8 low, #6 high)

LLC54AF10

120VAC

For Drain (pump-down) operation with fixed

sense resistance of 10 kΩ

LLC54BA

120VAC

For Fill (pump-up) operation with adjustable

sense resistance

LLC54BAS

120VAC

For Fill (pump-up) operation with adjustable

sense resistance and reverse connection

(#8 low, #6 high)

LLC56AA

230 VAC

For Drain (pump-down) operation with

adjustable sense resistance

If you don’t find the part you need, call us for a custom product 800-843-8848

Wiring Diagram

L1

N/L2

Metal Tank or use

additional Probe

HP = HIGH LEVEL PROBE

LP = LOW LEVEL PROBE

C = PROBE COMMON

V = VOLTAGE

Relay contacts are isolated.

Connect common to

conductive tank. Additional

probe is necessary for non-

conductive or insulated tanks.

LLC5 SERIES

8-PIN