© 2017 Littelfuse Protection Relays & Controls

Protection Relays

Pump Controls and Liquid Level Controls

www.littelfuse.com/

Rev: 1-A-020817

www.littelfuse.com/llc4

LLC4 SERIES

Description

The LLC4 combines resistance sensing circuitry with solid-state

timing to provide single probe level maintenance. On adjustable

units, the sensitivity adjustment allows accurate level sensing

while ignoring foaming agents and floating debris. Isolated

12VAC is provided at the probe to prevent electrolysis. A trickle

current of less than 1mA determines the presence or absence

of conductive liquid between the probe and common. The LLC4

Series can be used with many types of low voltage (resistance

changing) transducers to perform other control functions like

temperature limit control, photo limit control, condensation

sensing, and ice sensing.

Operation

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

touches the probe, the time delay begins. This time delay

prevents rapid cycling of the output relay and its load. At the

end of the time delay, the output relay energize and remain

energized until the liquid level falls below the probe level. The

output relay de-energize and remain de-energized until the liquid

rises and touches the probe.

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

probe, the time delay begins. This time delay prevents rapid

cycling of the output relay and its load. At the end of the time

delay, the output relay energize and remain energized until the

liquid level rises and touches the probe. The output relay then

de-energize and remain de-energized until the liquid level again

falls below the probe level.

Features & Benefits

FEATURES

BENEFITS

Isolated 12VAC probes

Prevents scale buildup on probe

Industry standard 8-pin

octal plug connection

Eliminates need for special connectors

Sensitivity adjustment

Provides accurate level sensing while ignoring foam

or floating debris

Wiring Diagram

Octal Plug-In Liquid Level Controls

L1

N/L2

Metal Tank or use

additional Probe

P = 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.

Ordering Information

MODEL

INPUT

VOLTAGE OPERATION

TIME

DELAY

SENSE RESISTANCE

MODEL

INPUT

VOLTAGE

OPERATION TIME

DELAY SENSE RESISTANCE

LLC42A10A 24VAC

Drain

10s

Adjustable 1 - 250kΩ

LLC44B1A

120VAC

Fill

1s

Adjustable 1 - 250kΩ

LLC42A1A

24VAC

Drain

1s

Adjustable 1 - 250kΩ

LLC44A60A

120VAC

Drain

60s

Adjustable 1 - 250kΩ

LLC42B15A

24VAC

Fill

15s

Adjustable 1 - 250kΩ

LLC44B20A

120VAC

Fill

20s

Adjustable 1 - 250kΩ

LLC44A10A 120VAC

Drain

10s

Adjustable 1 - 250kΩ

LLC44B2A

120VAC

Fill

2s

Adjustable 1 - 250kΩ

LLC44A15A 120VAC

Drain

15s

Adjustable 1 - 250kΩ

LLC44B30A

120VAC

Fill

30s

Adjustable 1 - 250kΩ

LLC44A1A

120VAC

Drain

1s

Adjustable 1 - 250kΩ

LLC44B4A

120VAC

Fill

4s

Adjustable 1 - 250kΩ

LLC44A2A

120VAC

Drain

2s

Adjustable 1 - 250kΩ

LLC44B5A

120VAC

Fill

5s

Adjustable 1 - 250kΩ

LLC44A4A

120VAC

Drain

4s

Adjustable 1 - 250kΩ

LLC44B5F100 120VAC

Fill

5s

Fixed 100kΩ

LLC44A5A

120VAC

Drain

5s

Adjustable 1 - 250kΩ

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

8-PIN