The TSURUMI LB-480A is a single-phase portable submersible dewatering pump from Tsurumi's LB-A series (Portable Dewatering Pump, Automatic Operation type). It has a 50 mm (2-inch) discharge and a 0.48 kW 2-pole motor. This listing is the single-phase 110V version, suited to construction sites running on 110V site power. A built-in electrode level relay starts the pump as soon as water touches the probe and stops it about one minute after the water drops below it. This helps prevent dry-running, so the pump suits unattended, intermittent drainage of site water, basements and sumps.
The LB-480A combines a semi-vortex urethane rubber impeller, a synthetic rubber pump casing and a flow-through top-discharge design, and weighs just 11 kg without cable. It handles clean water and site water carrying a small amount of sand and silt, seepage water and rain water, and passes solids up to 6 mm.
Selection note: the LB-480A has the same hydraulic performance as the standard LB-480; the only difference is the electrode auto-operation. The 110V and 220V versions are different factory builds and are not interchangeable: for 220V mains, choose the LB-480A (220V). The LB series is a dewatering pump, not a sewage or slurry pump, and is not suitable for domestic sewage with fibrous solids, septic tank waste or dense slurry.
Key features
- Electrode auto-operation: switched by an electrode level relay unit, with no float switch. When the water falls below the probe, a timer starts and the pump stops after about one minute; it restarts when the water touches the probe again. This prevents dry-running and the rapid on-off cycling caused by a turbulent water surface. Tsurumi's comparison shows up to 40% lower power use than non-automatic pumps.
- Rugged control unit: the level relay is resin-molded inside a rubber case and has been jobsite tested for more than 30,000 on-off cycles.
- Flow-through top discharge: water passes around the motor for maximum cooling, so the pump can run continuously at low water levels.
- 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 keeping 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.
- Built-in motor protector: a miniature thermal protector (MTP) cuts power on overheating or overcurrent and resets automatically once the motor cools.
- Anti-wicking cable entry: limits water creeping along the cable cores into the motor if the cable sheath is damaged.
- Abrasion-resistant wear parts: Tsurumi rates their durability as equivalent to its three-phase drainage pumps.
- Slim body: Tsurumi states that LB models fit inside an 8-inch pipe. Check the actual outside dimensions against the pipe bore before installation.
Applications
- Construction sites: excavation dewatering and removal of site water and seepage on 110V site power
- Basements and sumps: unattended intermittent drainage (clean water or water with a small amount of sand and silt only)
- Wells and well points: pumping inside an 8-inch pipe or well casing
- Storms and flooding: emergency drainage
Not suitable for: domestic sewage or water with fibrous solids, slurry or bentonite, seawater or salt water, oil, organic solvents, chemicals, potable water, or liquids outside 0–40 °C. The pump is neither explosion-proof nor dust-proof and must not be used where toxic, corrosive or explosive gas may be present.
Performance
At 50 Hz, the LB-480A's 11.0 m maximum head is the head at near-zero flow, and its 0.22 m³/min (about 13.2 m³/h, or 220 L/min) 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. The equivalent 60 Hz figures are 12.0 m and 0.24 m³/min; check the nameplate for the actual frequency. For more head or flow, consider the LB-800A 110V (50 Hz: 15.0 m, 0.31 m³/min).
Technical specifications
TSURUMI LB-480A single-phase 110V technical specifications
| Item | Specification |
|---|
| General |
|---|
| Model | LB-480A |
|---|
| Series | LB-A Portable Dewatering Pump (Automatic Operation type) |
|---|
| Discharge bore | 50 mm (2 in) |
|---|
| Discharge connection | Hose coupling (standard, vertical or inclined); male threaded coupling available on special order |
|---|
| Hydraulic performance |
|---|
| Max. head (at zero flow) | 11.0 m (50 Hz) / 12.0 m (60 Hz) |
|---|
| Max. capacity (curve end point) | 0.22 m³/min (13.2 m³/h) at 50 Hz / 0.24 m³/min (14.4 m³/h) at 60 Hz |
|---|
| Max. solids size | 6 mm |
|---|
| Automatic operation |
|---|
| Control | Electrode level relay unit (no float switch) |
|---|
| Starting water level | 115 mm |
|---|
| Stop | About 1 minute after the water falls below the probe |
|---|
| Electrical |
|---|
| Motor output | 0.48 kW |
|---|
| Power supply | Single-phase 110V (frequency as per nameplate) |
|---|
| Voltage tolerance | Within ±10% of the nameplate rated voltage |
|---|
| Motor | 2-pole dry-type induction motor, continuous-duty rated, insulation class E |
|---|
| Starting method | Capacitor run |
|---|
| Motor protection | Built-in miniature thermal protector (MTP), auto-reset |
|---|
| Cable | PVC (5 m in Tsurumi's global catalogue; length varies by regional build, check the unit supplied) |
|---|
| Seals and bearings |
|---|
| Shaft seal | Dual inside mechanical seals, silicon carbide (SiC) faces, oil-lubricated, with Oil Lifter |
|---|
| V-ring | Nitrile rubber (NBR) |
|---|
| Lubricant | Turbine oil ISO VG32, 155 ml |
|---|
| Bearings | Shielded ball bearings |
|---|
| Materials |
|---|
| Impeller | Semi-vortex, urethane rubber |
|---|
| Pump casing | Synthetic rubber |
|---|
| Shaft | 403 stainless steel |
|---|
| Liquid limits |
|---|
| Liquid | Clean water or site water with a small amount of sand and silt, seepage water and rain water |
|---|
| Liquid temperature | 0–40 °C |
|---|
| pH | 5–9 |
|---|
| Max. dry matter | 10% |
|---|
| Max. use pressure | 0.2 MPa (about 20 m, including discharge pressure) |
|---|
| Weight |
|---|
| Dry weight (excl. cable) | 11 kg |
|---|
Sources: Tsurumi single-phase portable pumps catalogue (IB101), the Tsurumi LB series operation manual and Tsurumi Europe LB series data. This is the single-phase 110V version; frequency, rated current and cable length are as per the nameplate and confirmation from the Hong Kong agent.
LB series comparison
Tsurumi LB / LB-A portable dewatering pump comparison (50 Hz)
| Model | Type | Power | Max. head | Max. capacity | Jaco versions |
|---|
| LB-480 | Standard | 0.48 kW | 11.0 m | 0.22 m³/min | 220V, 110V |
|---|
| LB-480A (this product) | Automatic (electrodes) | 0.48 kW | 11.0 m | 0.22 m³/min | 220V, 110V (this product) |
|---|
| LB-800 | Standard | 0.75 kW | 15.0 m | 0.31 m³/min | LB-800 |
|---|
| LB-800A | Automatic (electrodes) | 0.75 kW | 15.0 m | 0.31 m³/min | LB-800A, 110V |
|---|
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 probes (2 pcs): coil-spring type, cut to length to set a lower starting water level.
- 50 mm (2-inch) discharge hose: push it fully onto the hose coupling and secure it with the hose band.
- Earth leakage circuit breaker (ELCB) and thermal overload relay, set to the nameplate rated current (purchased separately).
- Male threaded coupling for pipe connection: available on special order.
Safety and installation
- Electrical work must be carried out by a registered electrical worker in line with local regulations, with earthing, an ELCB and a thermal overload relay. Never connect the earth wire to a gas pipe, water pipe, lightning rod or telephone earth.
- Match the supply voltage and frequency to the nameplate, within ±10% of the rated voltage. Never connect the 110V version to a 220V supply. When running from a generator, avoid powering other equipment from the same generator.
- Lift the pump by its handle with a rope or chain rated for its weight. Never lift, hang or pull it by the power cable or the level relay unit. Do not scratch, fold, twist, modify or bundle the cable, and do not use a damaged cable, plug or outlet.
- Never run the pump while anyone is in the water or sump, and never start it while it is suspended.
- Switch off and unplug before inspection or maintenance. Do not handle it with wet hands.
- The motor protector resets automatically: after a trip, disconnect the power and remove the cause. After a power cut, switch off the supply, because the automatic model restarts when power returns.
- Operate the pump upright, and stand it on a concrete block if it may draw in mud. Run the discharge hose as straight as possible with its outlet above the water surface to avoid kinks, air lock and siphoning back-flow.
- Do not run the pump against a closed valve or at abnormally low head. The surface gets hot during and right after operation; do not touch it with bare hands.
- Do not megger-test between the plug and the electrodes, or between the relay unit electrodes and the plug, as this damages the relay.
- Insulation resistance must be at least 20 MΩ on a new or repaired pump.
- Tsurumi advises obtaining the delivery specification sheet before use, as published specifications may change.
Wear parts and routine checks
- Main wear parts: impeller, pump casing, mechanical seals and V-ring. With long running in sandy water, the impeller and casing gradually wear and flow drops; drawing in large amounts of mud accelerates wear.
- Regularly check the oil condition in the oil chamber and inspect the cable and plug for damage. If the oil is cloudy or contains water, have the mechanical seals inspected promptly.
