© 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
Metal Ta nk or us
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
