The pneumatic level controller is used to control 1 level in liquids at atmospheric pressure. Model with electrical DPDT microswitch output. Besides liquids can control fluid mixtures that allow the tube to be cleaned after the level of mixture downs.

The liquid or mixture that is controlled must not emit vapours that rarify the entrapped air inside the tube. This could be provoke a misfunction of the device.

The controllers bases their function on the pneumatic outline. The controllers have an electric microswitch activated due to a membrane sensitive to pressure.

The action on the microswitch is carried out by the pressure of the air column entrapped inside the tube and the pressure chamber. Depending on the model, a water height of 40 mm.w.c. is sufficient to trigger the switch.

There are models with a micro pneumatic valve and there are other models that activate the switch due to a depression.

The models with sensitivity adjustment “SR”, the models with double signal “DS”and the models with “A99” switch have a regulation system with a spring that allows the adjusment of the sensitivity. Tightening the regulation nut to reduce the sensitivity and increase the strain of the liquid to activate the microswitch.

Make a hole wide enough to introduce the tube or fix it with the mounting accesory usuable.

Ensure of the water-tightness of the unions. Do not use tow or Teflon tapes, only screw the tube to the housing up to the base gasket.

In lateral mounting, ensure of a minimum height of the tube of 200 mm minimum after the elbow.


Approximate measures given in mm.

Technical data

NamePneumatic controller
TypeL-27 A99 – ref: 2404
L-27 A99 VITON – ref: 2404-0-908
Type of signalSingle signal, DPDT
Actuating pressureAbove the tube inlet;
±20 mm WG
L-27 A99Ascending at +70 mm WG
and descending at +40 mm WG
L-27 A99 VITONsubiendo a +85 y bajando a +60 mm.c.a.
Ascending at +85 mm WG
and descending at +60 mm WG
Maximum pressure+0,5 bar
Cable entryM20x1,5
Switching voltage250 V AC
Switching function1 NO + 1 NC
Capacity of the contact10 A / 250 V AC (for resistive loads)
For inductive or capacitive loads reduce at 50%
Ambient temperature-5° C – +60° C
Type of protectionIP53 according to DIN EN60529
Weight1,5 Kg
Housing and capAluminium (plastic under request)
Pressure chamber (base)Glass reinforced Polyester
(Under request Aluminium)
MembraneNBR (Under request Aluminium)
Base gasketEPDM
Xicle antiturbulence (under request)Brass
Tube connection screwG 1" female

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