JUMO NESOS R04 LS Bent Float Level Switch

A side-mounted float switch that reaches a long way into the tank

The JUMO NESOS R04 LS (type 408304) is a magnetic float switch in bent form. The float travels along a vertical guide tube, and its magnet actuates reed contacts inside the tube according to Archimedes’ principle. Because the guide tube leaves the tank through a short horizontal leg, the switch is installed from the side of a tank, oil sump or container, with a threaded or flanged connection. Up to five contacts, with SPST-NO, SPST-NC, SPDT or bistable functions, can be placed on a vertical tube of up to 2 m, and a Pt100, Pt1000 or temperature switch can be added so one process opening yields both level and temperature. The datasheet lists point-level measurement in storage tanks, oil sumps, diesel tanks, water treatment, shipbuilding and energy technology. Variants carry WHG, intrinsically safe Ex i or flameproof Ex d approvals.

Technical specifications

Reading the 15-step order code

The long code defines every geometry: 408304/ extension – electrical connection – cable length – process connection – tube diameter – L1 – L2 – float – number of floats – switching function – number of contacts – contact positions. Extension 262 gives WHG approval, 263 adds Ex i, 264 gives WHG with Ex d, 362 is Ex i, 462 is Ex d and 999 a special version. Electrical connection 115 is the Ex d terminal head, 130 and 131 are small and large cube housings, and 150, 160, 162 and 170 are PVC, silicone, silicone with M12 and PUR cables, with lengths such as 2000 or 5000 mm. The datasheet notes that the float density value listed under code 044 differs between the ordering list and the float table, so confirm that float before ordering where density matters. Number and position of contacts must be written in plain text, with minimum positions that depend on tube diameter.

Why a bent configuration

Straight float switches enter from the top of a tank, which is not always possible on closed vessels, oil sumps and engine rooms. The bent R04 leaves through a wall nozzle, and its adjustable tube height places alarms exactly where the plant operator needs them: low level, pump on, pump off, high level and overfill. Typical Gulf installations include diesel day tanks for generators, lube-oil reservoirs, condensate tanks and chemical dosing vessels. Contacts should always drive a contact-protection relay when inductive loads such as pumps or horns are switched. For continuous level see the published NESOS R20 LT, or browse the level instrumentation category for probes and transmitters.

To order a float switch, give the medium and its density, the tank height, and the number and position of switching points. The datasheet links the float type to the minimum density and to the pressure rating, so a wrong float may sink or be unsuitable for the pressure. State the guide tube diameter (8 or 12 mm), the horizontal and vertical lengths, the process connection, and the contact function: normally closed, changeover or normally open, with the bistable alternatives. For hazardous areas the Ex i or Ex d versions with WHG approval should be requested explicitly, and an integrated Pt100 or Pt1000 can be added.

Documents and quotation

The hosted document is JUMO data sheet 408304 (19 pages, English). Because geometry is configured per order, send the tank drawing, medium density, temperature and pressure so the switch points and float can be confirmed. Seven Star LLC is an independent supplier in Muscat and will respond with a quotation.