| Flow rate | m³/h or L/min | Compare the flow shown on the pump curve at the required total dynamic head—not just the pump’s maximum flow figure. | Unit conversion: 1 m³/h = 16.7 L/min. Estimate the volume to remove and the time available, then allow for actual site conditions. |
| Total dynamic head (TDH) | Metres (m) | Include vertical lift, pipe friction, fittings, and any outlet pressure requirement. Check that the pump curve covers both the required head and flow. | Static lift alone is not the full head requirement. Flow generally decreases as the required head increases. |
| Solids passage | Maximum particle size, mm | Check the manufacturer’s stated free-passage size and the pump’s intended water type. A screen or impeller design may affect what can pass. | Choose for the largest likely debris, not just the average. Stringy material, grit, and fibrous debris may clog a pump even when particles are below its stated passage size. |
| Water type and impeller | Clear, dirty, or solids-bearing water | Match the pump design to the fluid: clean-water drainage, general dirty-water drainage, or solids-handling service. | For water containing sediment or debris, verify the permitted particle size and whether abrasive solids are acceptable for the pump materials. |
| Hydraulic power check | Watts (W) | For water, hydraulic power is approximately 2.73 × flow (m³/h) × head (m), in watts. Electrical input must be higher because pumps are not 100% efficient. | Example: 10 m³/h at 10 m head requires about 273 W of hydraulic power. Use the pump’s rated input and performance curve to assess actual energy use. |
| Power supply | Voltage, phase, frequency, current | Confirm that the motor’s nameplate ratings match the available supply and that the circuit can handle its running and starting current. | Do not assume a pump is compatible based on voltage alone. Check local electrical requirements, plug or wiring arrangement, and protective devices. |
| Duty rating and thermal protection | Continuous or intermittent duty | Check the stated duty rating, allowable operating conditions, and whether thermal overload protection is built in. | For long or frequent pumping cycles, choose a model rated for that duty. Thermal protection does not make dry running or blocked operation safe. |
| Automatic operation | Float switch or control system | Compare start and stop levels, available space for float movement, and compatibility with the intended installation. | In a narrow pit, a float may become trapped. Confirm that the pump can start and stop at water levels that suit the site. |
| Minimum water level and residual water | Minimum operating depth or shut-off level | Check the specified minimum water level and how much water remains when pumping stops. | Drainage pumps do not all pump down to the same level. If a low residual level is important, confirm the stated operating limit for that model. |
| Materials and wear resistance | Wetted materials | Check casing, impeller, seals, and fasteners against the water’s chemistry and expected grit or abrasion. | Corrosive water and abrasive sediment can shorten service life. Confirm material compatibility rather than relying on appearance alone. |
| Submersion rating and installation | Ingress protection and permitted immersion conditions | Read the specified immersion depth, operating limits, cable requirements, and installation instructions. | An IPX8 marking indicates protection for immersion under conditions specified by the manufacturer; it does not by itself define unlimited depth or duration. |
| Best-fit pump type | Application match | Choose the pump category that meets the water-quality, flow, head, and duty requirements together. | Clear water: clean-water drainage pump. Water with moderate debris: dirty-water pump with suitable passage. Larger solids: solids-handling pump with a verified passage size. |