48
LRN Series
Reed float switch
Features
• High or low level sensing
• Normally open, nor mally closed or change over
contact action
• Ratings up to 100 W
• Operates in liquid down to S.G. of 0.65
• Internal or external fitting
• Easy to install
• Cost effective
Description
The Honeywell range of horizontal, vertical and right
angled float switches offers the design engineer a
combination of versatility and reed switch reliability. A
magnet located in the float is used to activate the reed
switch either on a rising or falling liquid level and the
design allows for high or low level sensing simply by
rotating the switch through 180°. A range of internal or
external mounting options is available and a universal
mounting kit allows both internal and external mounting.
Available in Nylon 6.6 and Glass Filled Polypropylene
materials and a range of switching options. LRN float
switches are suitable for use in the automotive, chemical,
petroleum and food processing industries in signalling
and control applications.
Typical applications
• Low coolant level sensing
• Fuel or oil level sensing
• Boiler level warning
• Solution monitoring
• Flood control
• Catering and vending machine
• Domestic appliance
• Medical equipment
Mechanical
Minimum operate angle 5° from mounting angle
(horizontal models)
Maximum release angle 40° from mounting angle
(horizontal models)
Shock * 50 g for 11 milliseconds duration
Vibration * 35 up to 500 Hz
Nominal cable length 0.5 m
Environmental Nylon 6.6 Diecast metal** Glassfilled****
body polypropylene
Operating Temperature Range -30 °C to -30 °C to -30 °C to
+130 °C +130 °C +110 °C
Minimum SG of liquid 0.85 0.85 0.65
Minimum Viscosity of Liquid 100 100 100
(centipoise)
Plastic Housing Water
absorption of equilibr ium
at 20 °C and 100 % RH 1.3 % 5.6 % 0.03 %
at 100 °C and 100 % RH 1.6 % 5.6 % <0.5 %
Heat distor tion temperature 180 °C 245 °C 105 °C
4.5 kg/cm2(67.6 psig)
Electrical
Switching options 0 1 2 3 4 5
Switch action SPST SPST SPDT SPST TRIAC TRIAC
Maximum Switching Voltage
(Vdc) 100 100 100 100
(VRMS) 120 250 70 120 250 250
Maximum Switching Current (A) 1.0 1.0 0.50 3.0 3.0 1.0
dc Contact Rating (W) 15 *** 15 *** 3 *** 100 *** 750 250
Minimum Breakdown Voltage
(Vdc) 300 800 200 400 - -
Initial Contact Resistance (Ω) 0.25 0.25 0.25 0.75 - -
* Reed Switch Only
** Diecast metal model is fitted with Nylon 6.6 float as standard
*** The switching perfor mance can be drastically affected if switch ratings
are exceeded. For inductive, capacitive and tungsten filament lamp loads,
derate by 50%. All switch ratings are at dc resistive loads.
**** For boiling water applications the maximum operating temperature limits are:-
Continuous boiling water 80 °C
Non continuous boiling water 100 °C
Technical information
Emergency cut out
Low level
High level
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Ordering information 987654321LRN -
1 Type of orientation
H Horizontal
V Vertical
R Right angled
2 Housing material
3 Nylon 6.6 (-30 to 130 °C)
4 Diecast metal body (-30 to 130 °C)
5 Glass filled Polypropylene (-30 to 110 °C)
3 Switching options
0 S.P.S.T. 120 Vr ms/1 A (15 W)
1 S.P.S.T. 250 Vr ms/1 A (15 W)
2 S.P.D.T. 70 Vrms/0.5 A (3 W)
3 S.P.S.T. 120 Vr ms/3 A (100 W)
4 Triac 250 Vr ms/3 A
5 Triac 250 Vr ms/1 A
4 Seal washer / Grommet
S Silicone
N Nitrile
5 Mounting options
0 M16 x 2 inter nal fit
1 M16 x 2 external fit (compression grommet)
2 1/2" NPT external fit
3 1/4" NPT inter nal fit
4 Universal kit (internal and external assemblies)
6 Termination
1 0.5 m PVC insulated leadwire
2 2 m PVC insulated leadwire
3 5 m PVC insulated leadwire
4 2 m two core cable
7, 8, 9 Customer specials
Mounting information
Care must be taken to ensure that the product is not
damaged due to excessive tightening of the fixing nut or
threaded bush.
Maximum torque limits are shown below.
Model Torque limit Maximum container
wall thickness
External fitting
(compression grommet) 2.0 lb ft (2.67 Nm) 0.16ins (4 mm)
See Note 1
External fitting (1/2" NPT) 5.0 lb ft (6.75 Nm) 1.00ins (25 mm)
See Note 2
Internal fitting 3.0 lb ft (4.0 Nm) 0.394ins (10 mm)
Internal fitting (1/4" NPT)
into tapered bush 5.0 lb ft (6.75 Nm) 0.50ins (12.7 mm)
through tank wall
with nut and washer 3.0 lb ft (4.0 Nm) 0.12ins (3 mm)See
See Note 2
Notes:
1. The compression grommet is suitable for a seal pressure of 70 psi.
2.When using a 1/2” NPT external fit version, the container wall thickness
must not exceed the length of male thread section of the switch. Some
pipe fittings have a small diameter outside the thread area which will
restrict entr y.This switch is designed to pass through a 1/2" NPT tap drill
0,718" diameter. Because the mounting bush is usually metal and the
switch is usually moulded plastic, care must be taken when using the 1/2"
or 1/4" NPT versions not to over tighten since this will cause damage to
the switch. A sealant such as PTFE tape should always be used on the
NPT versions. Ensure that the position orientation arrow on the 1/2" NPT
version is ver tical.
3. The float assembly on the horizontal models should never be removed
since this will affect the switching characteristics.
4. To reverse the switching action on horizontal models, simply rotate
through 180° observing or ientation indicator or arrow. On vertical and
right angled models, compress the float stop arms, remove and reverse
the float and reassemble. Movement of the float in the direction of the
position indication arrow closes the switch contacts at the end of float
travel.
Mounting position Stem position must be vertical ± 15°
(vertical & right angle models)
Mounting position ± 30° from horizontal
(horizontal models)
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Dimensions in inches (mm)
LRN - Horizontal models
External fitting 1/2" NPT
(American National Pipe Thread) Internal fitting 1/4" NPT
(American National Pipe Thread)
Internal fitting External fitting (compression grommet)
Installation hole size Installation hole size
Installation hole size
51
External fitting (compression grommet)
Dimensions in inches (mm)
LRN - Ver tical models
LRN - Right angle models
Internal fitting
External fitting (compression grommet) Internal fitting
