The TSURUMI KTZE43.7 is a three-phase submersible dewatering pump from Tsurumi's KTZE series (officially classed as a general construction pump, automatic operation type). It has a 100 mm (4-inch) discharge and a 3.7 kW 2-pole motor, and is the highest-flow model in the KTZE range. A built-in electrode level sensor and relay start the pump when water reaches the probe and stop it after the level falls, so no float switch or control panel is needed. With a grey cast-iron body and a semi-open high-chromium cast-iron impeller, it is built for unattended drainage of stormwater, groundwater, wash water and sand-carrying water on construction sites, in basements and in sumps (liquid 0–40 °C, solids up to 8.5 mm).
Selection note: the KTZE43.7 is the automatic version of the KTZ series. If start/stop is already handled by a float switch or control panel, the non-automatic KTZ43.7 is an option. With the same 3.7 kW motor, the KTZE43.7 is the volume model; where more head is needed, choose the 80 mm KTZE33.7 (28.9 m) or the 50 mm KTZE23.7 (36.4 m). If a lighter unit is needed, consider the lightweight aluminium KTVE35.5 (80 mm, 5.5 kW, 52 kg). The KTZE43.7 is a dewatering pump, not a slurry pump: it has no agitator and is not suitable for bentonite or settled sludge.
Key features
- Electrode automatic operation: the electrode probe and relay are built into the pump. When water touches the probe, current flows between the electrode and the pump body and the pump starts. Once the water drops below the probe, a built-in timer stops the pump about 1 minute later; if water touches the probe again in that time, the pump runs for one more minute. This prevents dry running and chattering caused by a turbulent water surface.
- Lower energy use: up to 40% less power consumption than non-automatic pumps, according to Tsurumi's own comparison. Actual savings depend on site conditions.
- Simple installation: just connect the power supply. Raise the pump on blocks to set a higher start level, or stage several pumps at different heights, for example in an underground car park.
- Top-discharge, side-flow design: the motor stays cooled even when exposed to air, and the slim body fits narrow sumps.
- Multi-directional hose coupling: the discharge can be set vertical or inclined to stop the 100 mm hose kinking.
- Double inside mechanical seals: silicon carbide (SiC) faces running in an oil chamber with Tsurumi's Oil Lifter, which keeps the seals lubricated and cooled down to one third of the normal oil level.
- Wear-resistant materials: high-chromium cast-iron semi-open impeller and ductile cast-iron suction cover; the 420 stainless steel shaft is quenched where it meets particles in the liquid.
- Motor protection: a built-in circle thermal protector (CTP) cuts the motor circuit directly on overheating or overcurrent; anti-wicking cable entry and cable clip.
Applications
- Construction sites: excavation and basement dewatering, temporary site drainage
- Basements and underground car parks: unattended automatic sump drainage
- Stormwater and groundwater: high-volume removal of flood water and seepage
- Quarries and aggregate yards: pit dewatering (water only, not slurry transfer)
- Wash water and sandy water: solids up to 8.5 mm
Performance
The 18.0 m maximum head is the head at near-zero flow, and the 1,432 L/min (about 85.9 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. Figures are from the Tsurumi Europe 400 V 50 Hz data sheet. The KTZE43.7 suits low-head, high-volume drainage; where the total head is higher, consider the KTZE33.7 (28.9 m) or the KTZE23.7 (36.4 m).
Technical specifications
TSURUMI KTZE43.7 technical specifications (50 Hz)
| Item | Specification |
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| General |
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| Model | KTZE43.7 |
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| Series | KTZE (cast iron, three-phase, electrode automatic submersible dewatering pump) |
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| Discharge bore | 100 mm (4 in) |
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| Discharge connection | Multi-directional hose coupling |
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| Automatic control |
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| Control method | Built-in electrode level sensor and relay (no float switch or control panel needed) |
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| Stop delay | About 1 minute after the water falls below the probe |
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| Starting water level | 435 mm |
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| Stop level | About 150 mm (Tsurumi UK data) |
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| Hydraulic performance |
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| Max. head (at zero flow) | 18.0 m |
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| Max. capacity (curve end point) | 1,432 L/min (about 85.9 m³/h) |
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| Max. solids size | 8.5 mm |
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| Electrical |
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| Motor output | 3.7 kW |
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| Motor | 2-pole dry-type induction motor, continuous-duty rated, insulation class F, IP68 |
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| Synchronous speed | 3,000 min⁻¹ (50 Hz) |
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| Power supply | 3-phase 50 Hz (official ratings 380/400/415 V; Hong Kong supply version voltage as per nameplate) |
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| Rated current | 380 V: 8.4 A; 400 V: 8.0 A; 415 V: 7.7 A (50 Hz) |
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| Starting method | Direct-on-line (DOL) |
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| Motor protection | Built-in circle thermal protector (CTP) |
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| Seals and lubrication |
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| Shaft seal | Double inside mechanical seals, SiC faces, with Oil Lifter |
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| Dust seal | NBR oil seal |
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| Lubricant | Turbine oil ISO VG32, 1,250 ml |
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| Materials |
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| Impeller | Semi-open, high-chromium cast iron |
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| Suction cover | Ductile cast iron (FCD50 / EN-GJS-500-7) |
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| Pump casing | Grey cast iron (FC200) |
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| Motor frame | Grey cast iron (FC150) |
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| Shaft | 420 stainless steel (quenched where it meets particles) |
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| Cable |
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| Cable length | 8 m (standard) |
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| Cable type | Chloroprene rubber sheath, 4 × 2.0 mm² |
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| Liquid limits |
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| Liquid | Stormwater, groundwater, wash water and sand-carrying water |
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| Liquid temperature | 0–40 °C |
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| Max. submersion depth | 25 m |
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| Dimensions and weight |
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| Dry weight (excl. cable) | 69 kg |
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| Plan dimensions (catalogue A × D, A incl. discharge) | 367 × 252 mm |
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| Overall height (catalogue B, to top of vertical discharge) | 770 mm |
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| Height to top of handle (catalogue H) | 717 mm |
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Sources: Tsurumi KTZ/KTZE series catalogue (IB107), Tsurumi Pumps Australia KTZE product guide, Tsurumi Europe KTZE43.7 data sheet (400 V 50 Hz) and Tsurumi UK data. Voltage, cable and rated current of the Hong Kong supply version are as per the nameplate and confirmation from the Hong Kong agent.
KTZE series comparison
Tsurumi KTZE series model comparison (50 Hz)
| Model | Discharge | Power | Max. head | Max. capacity | Dry weight |
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| KTZE21.5 | 50 mm | 1.5 kW | 21.7 m | 427 L/min | 39 kg |
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| KTZE22.2 | 50 mm | 2.2 kW | 26.0 m | 499 L/min | 41 kg |
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| KTZE23.7 | 50 mm | 3.7 kW | 36.4 m | 449 L/min | 69 kg |
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| KTZE31.5 | 80 mm | 1.5 kW | 14.4 m | 670 L/min | 38 kg |
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| KTZE32.2 | 80 mm | 2.2 kW | 20.5 m | 795 L/min | 40 kg |
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| KTZE33.7 | 80 mm | 3.7 kW | 28.9 m | 898 L/min | 69 kg |
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| KTZE43.7 (this product) | 100 mm | 3.7 kW | 18.0 m | 1,432 L/min | 69 kg |
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Optional accessories
- Multi-directional male threaded coupling, in place of the standard hose coupling for threaded pipe connections.
- Extension probe: made of coil spring and cut to length on site to lower the starting water level (Tsurumi UK states by about another 90 mm).
- Electrode probe cover: structural steel, fitted on site to protect the probe from impacts.
- Factory options (order separately): seawater-resistant kit (galvanic anode plus special impeller) and high-temperature version (liquid up to 80 °C). The standard model has neither.
Safety and installation
- Electrical connection must be made by a registered electrical worker in line with local regulations, with a correct earth and earth-leakage protection. Provide upstream short-circuit and overload protection; the motor's built-in CTP does not replace it.
- Per the Tsurumi Europe 400 V 50 Hz data, the KTZE43.7 draws about 7.7 A rated and about 58 A at start-up. Size generators and breakers for the starting current.
- Check the direction of rotation before first use. Wrong phase sequence on a three-phase pump reverses rotation and reduces performance; have an electrician swap two phases.
- The pump can start at any moment once the probe is wet. Always isolate the power before handling, lifting or servicing.
- Electrode control relies on the liquid conducting current between the probe and the pump body. Very low-conductivity liquid may not trigger a start, so test on site.
- The pump weighs 69 kg dry. Use lifting gear and lift by the handle only; never lift it by the power cable, and protect the cable from damage.
- Stand the pump on a firm base or blocks so it does not draw in mud and gravel.
- The standard model is not seawater-resistant. Do not use it for liquids above 40 °C, chemicals, oil, solvents, sewage containing fibres or flammable liquids, or in flammable or explosive atmospheres.
Wear parts and routine checks
- The impeller, suction cover and mechanical seals take the wear from sandy water; flow gradually drops after long running, so check them regularly.
- Check the oil level and condition in the oil chamber at regular intervals (turbine oil ISO VG32, 1,250 ml). If the oil is cloudy or contains water, have the shaft seals inspected promptly.
- The CTP resets automatically once the motor cools. Find the cause of any trip, such as a blockage, low voltage or a lost phase, before continuing.
