
Protection Relays
Pump Controls and Liquid Level Controls
LLC5 SERIES
Liquid Level Controls
Wiring Diagram
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 nonconductive or insulated tanks.
L1 N/L2
Ordering Information
MODEL
LLC52AA 24VAC
LLC52BA 24VAC
LLC54AA 120VAC
LLC54AAS 120VAC
LLC54AF10 120VAC
LLC54BA 120VAC
LLC54BAS 120VAC
LLC56AA 230 VAC
LINE
VOLTAGE
DESCRIPTION
For Drain (pump-down) operation with
adjustable sense resistance
For Fill (pump-up) operation with adjustable
sense resistance
For Drain (pump-down) operation with
adjustable sense resistance
For Drain (pump-down) operation with
adjustable sense resistance and reverse
connection (#8 low, #6 high)
For Drain (pump-down) operation with fixed
sense resistance of 10 kΩ
For Fill (pump-up) operation with adjustable
sense resistance
For Fill (pump-up) operation with adjustable
sense resistance and reverse connection
(#8 low, #6 high)
For Drain (pump-down) operation with
adjustable sense resistance
Metal Tank or use
additional Probe
8-PIN
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
LED status indicatior
Isolated 5A
SPDT contacts
Probes are protected from scale build up through
pulsed DC signal between the probes.
Visual indication of relay engagement in pump-up or
pump-down activity
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 bas e P1011-6 wit h its
corresponding hold down clips PSCRB8 do not co ver up the LED
window, but the socket base is not DIN rail mount able.
If you don’t find the part you need, call us for a custom product 800 -843-88 48
© 2016 Littelfuse Protection Relays & Controls
Rev: 1-A-062116

Protection Relays
Pump Controls and Liquid Level Controls
LLC5 SERIES
Accessories
PHST-38QTN Electrode
Designed for a maximum steam pressure of 240
PSI; 400° F. UL353 Recognized.
LLP-24 Threaded Probe (24”)
Threaded stainless steel probe measuring 24”
(61 cm) long. For use with PHST-38QTN liquid
level control electrodes.
Specifications
Control
Type Resistance sensing for high & low level
detection of conductive liquids
Sensing Voltage Pulsed DC at probe terminals
Sensing Resistance Factory fixed or adjustable to 100KΩ
Sensing Resistance
Tolerance Adjustable: 1K ±500Ω at low end;
100KΩ ±25%, 0% at high end
Factory fixed: ±10% or 500Ω whichever
is greater
Response Time Debounce time delay <1s
Input
Tolerance
24VAC -15%, +20%
120 & 230VAC -20%, +10%
AC Line Frequency 50/60 Hz
Output
Type Electromechanical relay
Form Isolated, SPDT
Rating 5A resistive @ 240VAC, 1/10 hp @ 240VAC
Protection
Isolation Voltage ≥ 1500V RMS between input, output, & probe
Mechanical
Mounting Plug-in socket
Dimensions H 60.7 mm (2.39”); W 45.2 mm (1.78”);
D 76.5 mm (3.01”)
Termination Octal 8-pin plug-in
Environmental
Operating/Storage
Temperature -20° to 60°C / -40° to 80°C
Weight 6 oz (170 g) approx.
© 2016 Littelfuse Protection Relays & Controls
Rev: 1-A-062116