The TSURUMI NK2-15 is a single-phase portable submersible dewatering pump from Tsurumi's NK series, sold by Tsurumi America as a 60 Hz model. It has an 80 mm (3-inch NPT male, cast-iron) discharge and a 1.5 kW (2 HP) 2-pole single-phase motor whose terminal board can be set for 110 V or 220 V. The NK series pairs a larger-output motor with abrasion-resistant wear parts in a slim body that fits confined spaces, and it is built for rain water, ground water and sand-carrying water (0–40 °C, solids up to 8.5 mm).
Selection note: the NK2-15 is a US 60 Hz model. It is not listed on Tsurumi's Hong Kong, Taiwan or global websites, where the current lineup is NK3-15, NK4-22 and NK4-22L. Tsurumi does not publish 50 Hz performance for the NK2-15, and Hong Kong mains are 50 Hz, so check the voltage and frequency on the nameplate before ordering. The equivalent 1.5 kW global model is the NK3-15. The NK series is a dewatering pump, not a sewage or slurry pump: with an 8.5 mm solids passage it is not suited to sewage containing fibrous solids, or to pumping slurry.
Key features
- Top-discharge, side-flow design: the motor stays cooled even when running exposed to air, and the slim overall diameter fits confined spaces. Keep the water level at or above 80 mm (C.W.L.) for continuous running.
- Dual inside mechanical seals: silicon carbide (SiC) faces running in an oil chamber, with Tsurumi's Oil Lifter, further protected by an oil seal running against a replaceable stainless steel shaft sleeve.
- Semi-vortex ductile-iron impeller: paired with a butadiene and natural rubber casing for abrasion resistance; passes solids up to 8.5 mm.
- Built-in thermal and amperage-sensing protector: cuts out the motor on overheating or overload to help prevent motor failure.
- Anti-wicking cable entry: limits water creeping along the cable cores into the motor if the cable sheath is damaged.
- Dual-voltage single-phase motor: capacitor start, rated 23.0 A at 110 V or 11.5 A at 220 V (60 Hz), continuous-duty rated.
- Permanently lubricated bearings: double-shielded C3 ball bearings (upper 6204ZZC3, lower 6305ZZC3).
Applications
- Construction sites: excavation, trench and temporary site drainage
- Rain water and ground water: removing standing water, including water carrying some sand
- Effluent transfer: transferring effluent
- Raw water supply: drawing water from rivers or lakes (not for drinking water)
- Rental fleets: a portable single-phase unit that moves easily between jobs
Performance
The maximum head of about 21 m is the head at near-zero flow, and the maximum capacity of about 0.42 m³/min (about 420 L/min or 25.2 m³/h) is the end point of the performance curve. Both are read from Tsurumi America's 60 Hz curve, and they do not occur together: actual flow falls as total head (static head plus hose friction loss) rises. Select the pump from the curve using your site's total head. Tsurumi does not publish 50 Hz performance for this model, so these figures cannot be applied directly on a 50 Hz supply.
Technical specifications
TSURUMI NK2-15 technical specifications (60 Hz)
| Item | Specification |
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| General |
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| Model | NK2-15 |
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| Series | NK (portable dewatering pump, single-phase) |
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| Discharge bore | 80 mm (3 in) |
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| Discharge connection | Cast-iron discharge connection, 3-inch NPT male thread |
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| Hydraulic performance |
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| Max. head (at zero flow) | Approx. 21 m (60 Hz) |
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| Max. capacity (curve end point) | Approx. 0.42 m³/min (approx. 420 L/min) (60 Hz) |
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| Max. solids size | 8.5 mm |
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| Impeller type | Semi-vortex |
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| Electrical |
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| Motor output | 1.5 kW (2 HP) |
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| Motor | 2-pole induction motor, continuous-duty rated, insulation class B |
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| Speed | Approx. 3,440 rpm (60 Hz) |
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| Power supply | Single-phase 110/220 V dual voltage, 60 Hz (voltage and frequency of supplied unit as per nameplate) |
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| Rated current | 23.0 A (110 V) / 11.5 A (220 V) |
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| Starting method | Capacitor start |
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| Motor protection | Built-in thermal and amperage-sensing protector |
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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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| Oil seal | Nitrile rubber (NBR), with replaceable stainless steel shaft sleeve |
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| Lubricant | Turbine oil ISO VG32 |
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| Bearings | Double-shielded C3 ball bearings (upper 6204ZZC3, lower 6305ZZC3) |
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| Materials |
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| Impeller | Ductile cast iron (ASTM A536 100-70-03) |
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| Pump casing | Butadiene rubber + natural rubber |
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| Wear ring | Butadiene rubber |
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| Shaft | 403 stainless steel |
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| Motor frame | Aluminium alloy |
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| Fasteners | 304 stainless steel |
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| Cable | Chloroprene sheath AWG12/3, approx. 10 m (32 ft) |
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| Liquid limits |
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| Liquid | Rain water, ground water, sand-carrying water |
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| Liquid temperature | 0–40 °C |
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| Weight and water level |
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| Dry weight (excl. cable) | 28.8 kg |
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| Min. water level for continuous running (C.W.L.) | 80 mm |
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Sources: Tsurumi America NK2-15 data sheet (60 Hz) and the Tsurumi KTV/KTVE/NK series operation manual (B-10276). Voltage and frequency of the unit supplied in Hong Kong are as per the nameplate.
NK series comparison
Tsurumi NK series model comparison
| Model | Discharge | Power | Max. head | Max. capacity | Notes |
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| NK2-15 (this product) | 80 mm (3" NPT) | 1.5 kW | Approx. 21 m (60 Hz) | Approx. 0.42 m³/min (60 Hz) | US 60 Hz model, 110/220 V dual voltage |
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| NK3-15 | 50 mm (global standard); 80 mm on US version | 1.5 kW | 20.0 m (50 Hz) / 21.0 m (60 Hz) | 0.42 m³/min (50/60 Hz) | Current global model |
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| NK4-22 | 50 mm (global standard); 80 mm on US version | 2.2 kW | 24.0 m (50 Hz) / 26.0 m (60 Hz) | 0.525 m³/min (50 Hz) / 0.495 m³/min (60 Hz) | Current global model |
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| NK3-22L | 80 mm (3" NPT) | 2.2 kW | Approx. 18 m (60 Hz) | Approx. 0.80 m³/min (60 Hz) | US 60 Hz model, 220 V, cast-iron casing |
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Optional accessories
The following accessories are listed by Tsurumi America for the NK series. Please contact us for availability in Hong Kong.
- External float switch: TS-304 for 110 V (the data sheet also lists TS-301). The NK series itself has no automatic version.
- Sand Kit: a high-chrome cast-iron impeller that agitates sand to prevent sand lock (the sand-kit version is designated NK2-15SK).
- Discharge hose: 3-inch NPT discharge hose.
- Electrical protection (user-supplied): a dedicated earth-leakage circuit breaker and a thermal overload relay set to the nameplate rated current.
Safety and installation
- Fit a dedicated earth-leakage circuit breaker and a thermal overload relay, and earth the pump securely. Never earth it to a gas pipe, water pipe, lightning rod or telephone earth.
- Electrical connection, including setting the 110 V / 220 V wiring, must be done by a registered electrical worker in line with local regulations. Keep the supply within ±5% of the nameplate voltage; on a generator, do not run other equipment from the same generator.
- Carry the pump by its handle. Never lift or drag it by the cable, and do not start it while it is suspended.
- Do not run the pump dry, below the C.W.L. (80 mm), or against a closed gate valve.
- Secure the discharge hose so it cannot whip. If the pump could be buried in sediment, stand it on a solid base such as a concrete block.
- Never run the pump while anyone is in the pool, tank or sump.
- The pump is neither dust-proof nor explosion-proof: do not use it where toxic, corrosive or explosive gas is present. Do not pump oil, seawater, salt water, chemicals, corrosive liquids, organic solvents, flammable liquids, liquids above 40 °C, or drinking water.
- The pump surface may be hot during and after operation.
- The pump restarts automatically when power returns after an outage. Switch off the power before servicing, during outages and for long idle periods.
Wear parts and routine checks
- Daily: check that the running current is at or below the rated value and the voltage is within ±5% of the nameplate.
- Monthly: measure insulation resistance; it must be at least 1 MΩ in service (at least 20 MΩ when new).
- Check the oil every 6 months or 3,000 hours, and change it every 12 months or 6,000 hours with VG32 turbine oil. If the oil has turned milky white, water may be getting past the seals, so have the mechanical seals inspected promptly.
- Mechanical seal replacement must be carried out by a dealer or Tsurumi service; an overhaul is recommended every 2 to 5 years.
- Pumps left standing in water should be run at least once a week to prevent seizing.
