A good submersible pump specification describes the job the pump must do, the conditions it will work in and the evidence you want before shipment. It covers the duty point, the borehole and water, the power supply, materials, motor and cable, testing, documents and packing.
Send the same specification to every supplier. It makes quotes comparable, and it becomes the reference for inspection and warranty claims.
1. Duty and site conditions
- The duty point: flow in a stated unit and total head in metres at that flow.
- The acceptable operating range, if the pump will run at more than one duty.
- The minimum borehole or casing internal diameter, and the maximum pump outside diameter including the cable guard.
- The pumping water level, the setting depth and the maximum installation depth.
- Water quality: sand content limit, temperature range, and whether the water is saline, acidic or aggressive.
- Whether the pump is for drinking water, which may need approved materials in your market.
2. Power supply and motor
- Phase, voltage and frequency, with the voltage tolerance the motor must handle.
- Rated motor power in kW, with a margin above the maximum power drawn across the operating range.
- Motor type: water-filled rewindable or oil-filled, and the winding wire material and insulation.
- The efficiency class, if your market requires one, such as IE2 or IE3.
- The starting method and control panel: direct on line, star-delta, soft starter or VFD, with dry-run, overload and phase protection.
- Drop cable size, length and insulation, sized for voltage drop at the setting depth.
3. Materials and construction
- The material of each wet part: outer shell, impellers, diffusers, shaft, coupling, strainer and fasteners, with stainless steel grades named.
- The mechanical seal type and face materials, and any sand guard.
- The non-return valve, if built into the pump.
- Coatings and corrosion protection for cast iron parts.
- The standard the pumpset is built to, such as IS 8034 or an equivalent in your market.
Our guide to pump materials explains the choices, including where stainless steel is worth the extra cost.
4. Testing and documents
- The performance test standard and acceptance grade, for example a stated grade under ISO 9906, at your voltage and frequency.
- How many pumps are tested, and whether you or an inspector will witness them.
- Routine motor tests on every unit: insulation resistance, high-voltage test, winding resistance and no-load current.
- Documents per shipment: test reports with serial numbers, the declaration of conformity where needed, manuals in your languages and a spare parts list with part numbers.
What a test report should contain is covered in pump performance test reports.
5. Marking, packing and commercial terms
- Nameplate content: brand, model, serial number, rating, voltage, frequency, duty point and any required marks.
- Serial number format and records, so every pump can be traced to its test.
- Packing: carton or crate type, inserts, port caps, labels and palletising.
- Warranty period and start date, and the claim procedure.
- A rule that no change to design, materials or sub-suppliers is allowed without your written approval.
Keep it practical
A specification does not need to be long, but every line should be checkable. "Good quality" cannot be inspected. "Copper winding, ISO 9906 grade 3B test on 10% of units at 400 V 50 Hz" can. If you sell a range, use one master specification with a table of models and duty points.
Attach it to the purchase contract so it carries legal weight. The broader contract points are covered in what an engineering purchase contract should include.
Next step
We can help you draft the specification, send it to shortlisted makers and inspect against it before every shipment. Book a free sourcing review.