The TSURUMI HSZ2.75S 110V is the automatic version of Tsurumi's HS-series portable dewatering pump, a submersible single-phase portable drainage pump. This unit is the single-phase 110V 50Hz supply version, with a 50 mm discharge and a 0.75 kW 2-pole single-phase motor. A float switch is fitted to the pump: it starts the pump when the water rises to the set level and stops it when the water drops back, which cuts out dry-running, saves power and extends service life. Performance is identical to the manual HS2.75S: 18 m maximum head and 230 L/min maximum capacity (50 Hz).
Selection note: the HSZ2.75S is a dewatering pump, not a sewage pump or a slurry pump, so it is not suitable for raw sewage, fibrous waste or settled sludge. The 110V version needs a 110V 50Hz supply (on site, usually from an isolating transformer). For a 230V supply, choose the HSZ2.75S (230V); never mix supply voltages. If you do not need automatic operation, choose the manual HS2.75S 110V. For settled sand and mud, choose the HSD2.55S slurry pump, which has a high-chrome impeller and agitator.
Key features
- Automatic float-switch operation: a single float switch starts and stops the pump, so it runs unattended without dry-running.
- Agitator prevents air lock: a sintered-alloy agitator on the shaft prevents the air lock that semi-vortex pumps are prone to.
- Side discharge with spiral casing: the external side outlet and spiral pump casing let water carrying solids pass through more smoothly, with a 7 mm solids passage.
- Abrasion-resistant parts: wear-prone parts are made of abrasion-resistant material, which Tsurumi says gives durability equivalent to its three-phase drainage pumps. The impeller is a urethane-rubber semi-vortex type.
- Dual inside mechanical seals: silicon carbide (SiC) faces running in an oil chamber, with Tsurumi's Oil Lifter keeping the seal faces lubricated and cooled down to about 1/3 of the normal oil level. An NBR V-ring dust seal is also fitted.
- Built-in circle thermal protector (CTP): cuts the motor circuit directly on overheating or overcurrent.
- Anti-wicking cable entry and cable clip: stops water creeping into the motor by capillary action if the sheath is damaged or the cable end is submerged, and prevents condensation inside the motor housing. The cable clip protects against tugging.
- Resin stand: prevents scratching of the floor.
Applications
- Construction and civil works sites: automatic dewatering of excavations and standing site water, on a 110V site supply
- Sumps and collection points: where water collects intermittently, with the float switch starting and stopping the pump automatically
- General pumping and drainage: water drainage only; not for sewage, slurry, seawater, hot liquids or chemicals
Performance
The 18 m maximum head is the head at near-zero flow, and the 230 L/min (about 13.8 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, so select the pump from the performance curve using your site's total head. Figures are for 50 Hz; Tsurumi UK lists the same flow and head for the 110V and 230V versions.
Technical specifications
TSURUMI HSZ2.75S 110V technical specifications (50 Hz)
| Item | Specification |
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| General |
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| Model | HSZ2.75S (110V version) |
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| Series | HS series, portable dewatering pump (automatic) |
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| Discharge bore | 50 mm |
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| Discharge connection | Hose coupling (standard); male threaded pipe coupling on special request |
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| Operation | Automatic start/stop by float switch |
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| Hydraulic performance |
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| Max. head (at zero flow) | 18 m |
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| Max. capacity (curve end point) | 230 L/min (approx. 13.8 m³/h) |
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| Max. solids size | 7 mm |
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| Impeller | Semi-vortex, urethane rubber |
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| Electrical |
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| Motor output | 0.75 kW |
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| Power supply | Single-phase 110V 50 Hz |
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| Motor | Dry-type 2-pole induction motor, continuous-duty rated, insulation class E |
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| Starting method | Capacitor run |
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| Synchronous speed | 3,000 min⁻¹ (50 Hz) |
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| Motor protection | Built-in circle thermal protector (CTP) |
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| Standard cable | 5 m PVC cable (catalogue standard) |
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| Seals and materials |
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| Shaft seal | Dual inside mechanical seals, silicon carbide (SiC) faces, oil-lubricated, with Oil Lifter |
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| V-ring (dust seal) | Nitrile butadiene rubber (NBR) |
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| Lubricant | Turbine oil ISO VG32, 160 ml |
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| Pump casing | Ductile cast iron |
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| Agitator | Sintered alloy |
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| Shaft | 403 stainless steel |
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| Stand | Resin |
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| Dimensions, weight and water levels |
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| Dry weight | 16.4 kg |
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| Dimensions (A × D × H) | 285 × 184 × 394 mm |
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| Min. required space (F) | 370 mm |
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| Float switch levels | FL1 150 mm (min.) / FL2 475 mm (max.) |
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| Continuous running water level (C.W.L.) | 90 mm |
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| Liquid limits (Tsurumi Europe data) |
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| Liquid | Drainage water |
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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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Sources: Tsurumi single-phase portable pumps catalogue (IB101), Tsurumi Hong Kong and Tsurumi Global product pages, and Tsurumi Europe and Tsurumi UK product data (50 Hz). Tsurumi notes that published data may differ from the actual product, so confirm against the delivery specification sheet and the nameplate before use.
HSZ series (automatic) 110V model comparison
Tsurumi HSZ series 110V model comparison (50 Hz)
| Model | Discharge | Power | Max. head | Max. capacity | Dry weight |
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| HSZ2.4S 110V | 50 mm | 0.4 kW | 12 m | 200 L/min | 11.3 kg |
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| HSZ2.75S 110V (this product) | 50 mm | 0.75 kW | 18 m | 230 L/min | 16.4 kg |
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| HSZ3.75S 110V | 80 mm | 0.75 kW | 18 m | 300 L/min | 16.8 kg |
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| HSZ3.75SL 110V | 80 mm | 0.75 kW | 10.8 m | 580 L/min | 19.6 kg |
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Optional accessories
- 50 mm (2-inch) discharge hose, sized to the outlet bore.
- Male threaded coupling for pipe connection, available on special request.
- 110V 50Hz site isolating transformer, where no 110V supply is available.
Safety and installation
- Connect only to an earthed single-phase 110V 50Hz supply; never connect to 230V. An outlet with earth-leakage (RCD) protection is recommended.
- Lift and position the pump by its handle. Never lift it by the power cable, and replace or repair a damaged cable.
- Make sure the float can move freely and cannot catch on the cable or a wall, and allow the minimum required space F of 370 mm.
- For continuous duty, keep the water level at or above 90 mm. The built-in thermal protector is a safeguard only; do not run the pump dry for long periods.
- Stand the pump on firm ground or a platform so it does not sink into silt.
- Do not use in flammable or explosive atmospheres, and do not pump flammable, corrosive or hot liquids or seawater.
Wear parts and routine checks
- Main wear parts: impeller, agitator, mechanical seals and V-ring. Long running in sandy water gradually wears the impeller and flow drops.
- Always isolate the power before inspection or servicing. Check and replace the seal oil (turbine oil ISO VG32, 160 ml) periodically. The Oil Lifter only maintains lubrication down to about 1/3 of the oil level; if the oil is cloudy or contains water, have the shaft seals inspected promptly.
- Check regularly that the float switch operates correctly and that the cable sheath is undamaged.
