Protection Relays
Pump Controls and Liquid Level Controls
LLC4 SERIES
Octal Plug-In Liquid Level Controls
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.
8-PIN
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.
Wiring Diagram
P = Probe
C = Probe Common
V = Voltage
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.
Relay contacts are isolated.
Connect common to
conductive tank. Additional
probe is necessary for
non-conductive or
Metal Tank or use
additional Probe
insulated tanks.
Features & Benefits
L1
N/L2
FEATURES
BENEFITS
Isolated 12VAC probes
Prevents scale buildup on probe
Industry standard 8-pin
octal plug connection
Eliminates need for special connectors
Provides accurate level sensing while ignoring foam
or floating debris
Sensitivity adjustment
Ordering Information
INPUT
TIME
INPUT
MODEL
TIME
MODEL
OPERATION
SENSE RESISTANCE
OPERATION
SENSE RESISTANCE
VOLTAGE
DELAY
10s
1s
VOLTAGE
DELAY
LLC42A10A 24VAC
LLC42A1A 24VAC
Drain
Drain
Fill
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
LLC44B1A
LLC44A60A
LLC44B20A
LLC44B2A
LLC44B30A
LLC44B4A
LLC44B5A
120VAC
120VAC
120VAC
120VAC
120VAC
120VAC
120VAC
Fill
1s
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Adjustable 1 - 250kΩ
Fixed 100kΩ
Drain
Fill
60s
20s
2s
LLC42B15A 24VAC
LLC44A10A 120VAC
LLC44A15A 120VAC
15s
10s
15s
1s
Drain
Drain
Drain
Drain
Drain
Drain
Fill
Fill
30s
4s
LLC44A1A
LLC44A2A
LLC44A4A
LLC44A5A
120VAC
120VAC
120VAC
120VAC
Fill
2s
Fill
5s
4s
LLC44B5F100 120VAC
Fill
5s
5s
If you don’t find the part you need, call us for a custom product 800-843-8848
© 2017 Littelfuse Protection Relays & Controls
www.littelfuse.com/llc4
Rev: 1-A-020817