Electromechanical level switch TUBA 1" 1/4

floatsubmergedfor liquids

Overview
The TUBA-1-1/4 tubular float level switch is designed for reliable level detection in tanks, cisterns and confined vessels where access is limited. Its small Ø36 mm diameter allows passage through narrow side openings while providing precise switching for pump control, alarms and automation.

Operating principle
The tubular float moves with the liquid level and actuates an internal mechanical switch when the predefined angle is reached. The switch provides common, normally open and normally closed contacts to select fill or drain logic. The device features a tight switching angle (±20°) for accurate level control.

Installation modes
The TUBA-1-1/4 can be: fixed to a stem, suspended vertically on its cable with external ballast, or mounted horizontally on tank walls using a gland or cable gland adapter.

Fill and drain operation
In fill mode the internal contact is closed in the low position to start pumps. In drain mode the contact acts in the opposite sense to stop pumps at a high level. The float may be used standalone or in pairs for min/max control.

Ballast positioning
Adjusting the ballast position on the cable changes the float travel and trigger height. Proper ballast placement optimizes switching angle and performance in turbulent or slightly loaded liquids. Typical adjustment examples: Y min 10 cm -> X ≈ 30–35 cm; Y max 30 cm -> X ≈ 60–65 cm.

Mounting and fixation
Use the FIXCAB accessory or a suitable gland to secure cable suspension and avoid damaging the cable sheath. Ensure any fixation does not create capillary ingress paths.

Electrical connection
External connections must be made in a sealed junction box outside the tank in wet or outdoor environments. Cable extensions are possible with standard signal cable; factory lengths are available to avoid in-tank splices.

Key points

• Switching angle ±20° for precise detection
• Tubular Ø36 mm profile for insertion through very narrow openings
• IP68 sealing for submerged installations
• Custom cable lengths and ballast options available

Recommended accessories

• FIXCAB cable fixation
• Adjustable ballast 175 g / 250 g (resin-filled)
• Level control relay (e.g. AT-DR07) and pump control modules

Technical specifications

• Model: TUBA-1-1/4
• Float diameter: Ø36 mm
• Switching angle: ±20°
• Allowed fluid density: 0.75–1.50 kg/dm³
• Rated supply: 250 VAC/VDC 50/60 Hz
• Cut-out rating: 12 (6) A (resistive/inductive)
• Housing: copolymer polypropylene
• Cable: 3 x 1 mm² neoprene
• Weight (float without cable): ~75 g
• Ballast (optional): 175 g resin-filled
• Maximum installation depth: 55 m
• Ingress protection: IP68
• Typical cable lengths: 2, 3, 5, 6, 10, 13, 15, 20, 25 m