The TSURUMI LB-480A is a single-phase submersible dewatering pump from Tsurumi's LB-A series (officially classed as a Portable Dewatering Pump, Automatic Operation type). It has a 50 mm (2-inch) discharge and a 0.48 kW single-phase motor. A built-in electrode-type level relay unit runs the pump while the probe is submerged, stops it about one minute after the water falls below the probe, and restarts it when the water touches the probe again. There is no float switch, which makes it a good fit for unattended drainage of site water, seepage and rain water. This listing is the 220V version.
Every LB model is slim enough to fit inside an 8-inch pipe or well casing. The top-discharge, flow-thru design gives maximum motor cooling, so the pump can run continuously at low water levels. Wear parts are made of abrasion-resistant materials, and Tsurumi rates their durability as equivalent to its three-phase dewatering pumps.
Selection note: the LB-480A has the same performance as the standard LB-480; the only difference is the electrode auto-operation control. It senses water with electrodes, not a float switch. It is a dewatering pump, not a sewage pump: the impeller passes solids up to 6 mm only, so it is not suitable for domestic sewage with fibrous solids, septic tanks, sewage pits or slurry. For sites on a 110V supply, choose the LB-480A (110V).
Key features
- Electrode auto-operation: Tsurumi's innovative electrode-type level relay unit keeps the pump running for about one minute after the water drops below the probe, which prevents dry-running and the chattering caused by a turbulent water surface. Tsurumi's comparison shows up to 40% lower power use than non-automatic pumps, and longer life for wear parts.
- Adjustable starting level: the standard starting water level is 115 mm. The optional extension probe (coil-spring type, cut to length) lets you set a lower starting level.
- Top-discharge, flow-thru design: efficient motor cooling for continuous running at low water levels, and a slim cylindrical body for deep-well dewatering inside an 8-inch casing.
- Multi-directional hose coupling: set the discharge vertical or inclined so the hose does not kink.
- Dual inside mechanical seals: silicon carbide (SiC) faces in an oil chamber, with Tsurumi's original Oil Lifter that keeps the seals lubricated down to about one third of the normal oil level.
- V-ring dust seal: a nitrile rubber (NBR) V-ring keeps abrasive particles away from the mechanical seal.
- Urethane semi-vortex impeller: abrasion-resistant urethane rubber for site water carrying sand and silt.
- Built-in motor protector: a miniature thermal protector (MTP) trips on overheating or overcurrent, including overheating from dry-running, and resets automatically once the motor cools.
- Anti-wicking cable entry: limits water creeping along the cable cores into the motor.
Applications
- Construction sites: excavation and foundation pit dewatering, site water containing sand and silt
- Seepage and rain water: automatic drainage of sumps and ponded rain water
- Well-point and deep-well dewatering: fits inside an 8-inch pipe or well casing
- Unattended drainage: temporary drainage points where the pump should start and stop with the water level
For clean water or water containing sand and silt only (up to 10% dry matter, pH 5–9, 0–40 °C). Not for seawater or salt water, oil, organic solvents, chemicals, potable water, domestic sewage or slurry. The electrodes rely on the conductivity of the water, so they may not detect high-resistivity liquids such as purified or distilled water.
Performance
At 50 Hz, the 11 m maximum head is the head at near-zero flow, and the 220 L/min (0.22 m³/min, about 13.2 m³/h) maximum capacity is the end point of the performance curve. The two do not occur together: actual flow falls as total head (static head plus hose friction loss) rises. Select the pump from the performance curve using your site's total head. For more head or flow, consider the LB-800A (15 m max. head, 310 L/min max. capacity at 50 Hz).
Technical specifications
TSURUMI LB-480A technical specifications (50 Hz)
| Item | Specification |
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| General |
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| Model | LB-480A |
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| Series | LB-A (portable dewatering pump, automatic operation type) |
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| Discharge bore | 50 mm (2 in) |
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| Discharge connection | Hose coupling (standard, vertical or inclined); male threaded pipe coupling on special request |
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| Hydraulic performance |
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| Max. head (at zero flow) | 11 m |
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| Max. capacity (curve end point) | 220 L/min (0.22 m³/min / approx. 13.2 m³/h) |
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| Max. solids size | 6 mm |
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| Automatic operation |
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| Control | Electrode-type level relay unit (no float switch) |
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| Starting water level | 115 mm (from the pump base) |
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| Stop | About 1 minute after the water falls below the probe |
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| Electrical |
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| Motor output | 0.48 kW |
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| Motor | 2-pole dry-type induction motor, continuous-duty rated, insulation class E |
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| Power supply | Single-phase, 220V version (voltage and frequency as per nameplate; supply within ±10% of rated voltage) |
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| Starting method | Capacitor run |
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| Motor protection | Built-in miniature thermal protector (MTP), auto-reset |
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| Cable | PVC, 5 m (Tsurumi catalogue standard) |
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| Seals and bearings |
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| Shaft seal | Dual inside mechanical seals, silicon carbide (SiC) faces, oil-lubricated, with Oil Lifter |
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| Lubricant | Turbine oil ISO VG32 (non-additive), 155 ml |
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| Dust seal | V-ring, nitrile butadiene rubber (NBR) |
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| Bearings | Shielded ball bearings |
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| Materials |
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| Impeller | Semi-vortex, urethane rubber |
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| Pump casing | Synthetic rubber |
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| Shaft | 403 stainless steel |
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| Liquid limits |
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| Liquid | Clean water, or site water, seepage and rain water containing sand and silt |
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| Liquid temperature | 0–40 °C |
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| pH | 5–9 |
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| Max. dry matter | 10% |
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| Max. use pressure | 0.2 MPa (approx. 20 m, submergence plus discharge pressure) |
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| Dimensions and weight |
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| Dry weight (excl. cable) | 11 kg |
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| Dimensions | A 233 mm, A1 189 mm, height 286 mm; 223 mm overall diameter including the level relay unit |
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| Installation space | Fits inside an 8-inch pipe or well casing |
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Sources: Tsurumi single-phase portable pumps catalogue (IB101), Tsurumi LB series operation manual and Tsurumi Europe LB series data (50 Hz). Tsurumi advises that published specifications may change; confirm against the delivery specification sheet and the nameplate before use.
LB series comparison
Tsurumi LB / LB-A series model comparison (50 Hz)
| Model | Operation | Power | Max. head | Max. capacity | Dry weight |
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| LB-480 | Standard | 0.48 kW | 11 m | 220 L/min | 10.4 kg |
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| LB-480 (110V) | Standard | 0.48 kW | 11 m | 220 L/min | 10.4 kg |
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| LB-480A (this product, 220V) | Automatic | 0.48 kW | 11 m | 220 L/min | 11 kg |
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| LB-480A (110V) | Automatic | 0.48 kW | 11 m | 220 L/min | 11 kg |
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| LB-800 | Standard | 0.75 kW | 15 m | 310 L/min | 13.1 kg |
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| LB-800A | Automatic | 0.75 kW | 15 m | 310 L/min | 13.7 kg |
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| LB-800A (110V) | Automatic | 0.75 kW | 15 m | 310 L/min | 13.7 kg |
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What's in the box
- LB-480A pump with cable, level relay unit and hose coupling × 1
- Hose band × 1
- Operation manual × 1
Optional accessories
- Extension probe × 2 (coil-spring type, cut to length to lower the starting water level)
- 50 mm (2-inch) discharge hose, secured with the supplied hose band
- Earth leakage circuit breaker (ELCB) and a thermal overload relay set to the rated current (purchased separately)
Safety and installation
- Electrical work must be carried out by a registered electrical worker in line with local regulations. Always earth the pump and install an ELCB and an overload relay. Never connect the earth wire to a gas pipe, water pipe, lightning rod or telephone earth.
- The 220V and 110V versions are not interchangeable. Make sure the nameplate voltage and frequency match the supply, within ±10% of the rated voltage. On a generator, avoid running other equipment at the same time.
- Lift the pump by its handle with a rope or chain rated for its weight. Never lift or hang it by the cable or the level relay unit, and do not scratch, fold, twist or modify the cable.
- Never start the pump while it is suspended, and never run it while anyone is in the sump or water.
- The automatic model restarts by itself when power returns after an outage, so switch off the supply during a power cut. Isolate and unplug the pump before inspection or servicing, and do not handle it with wet hands.
- The built-in motor protector resets automatically. After a trip, disconnect the power and remove the cause.
- Do not megger-test between the plug and the electrodes of the level relay unit, as this damages the relay. Insulation resistance on a new or repaired pump should be at least 20 MΩ.
- Operate the pump upright. If it may draw in mud, stand it on a concrete block. Run the discharge hose as straight as possible with its outlet above the water surface to avoid kinks, air lock and backflow.
- The pump is neither explosion-proof nor dust-proof. Do not use it where toxic, corrosive or explosive gas may be present, and never for potable water. The body gets hot during and right after operation; do not touch it with bare hands.
Wear parts and routine checks
- Lubricant: change the turbine oil ISO VG32 (non-additive, 155 ml) every 12 months or 2,000 running hours, whichever comes first.
- Mechanical seal: if the oil turns milky or contains water, have the pump dismantled and the seal replaced.
- V-ring and shaft sleeve: replace when worn; replace the V-ring at every disassembly or inspection.
- Packing and O-rings: replace at every disassembly or inspection.
- Impeller: long running in sandy water gradually wears it and flow drops, so check it regularly. Keep wire, nails, cord and similar debris away from the pump to prevent clogging.
