Selection guide / common questions

These two figures help narrow the initial selection.Flowis the volume of water required per hour (m³/h);Headis the energy expressed as an equivalent height of water (m).

FlowEstimate from demand: draining a 30 m³ tank in two hours requires 15 m³/h. For domestic supply, estimate demand at the outlets; 0.6 m³/h per tap is an illustrative value that needs checking against actual use.

Head is not just building height. Pipework resistance and required outlet pressure also contribute:

Example: a basement-to-rooftop installation has about 20 m of vertical lift and 40 m of pipe with several bends. Including pipe losses could bring the required head to around 30 m rather than 20 m. Verify the actual system losses before selecting the pump.

Check the supply at the installation. Homes and small shops in China commonly use 220 V single-phase; factories, construction sites and irrigation installations often have 380 V three-phase.

A similar specification may be offered in both versions with only one letter different.Always confirm the power supply before purchasing. Connecting a motor to the wrong voltage can prevent operation or cause damage; electrical connections must match the nameplate and be checked by qualified personnel.

Connection size describes the inlet or outlet diameter. Common nominal equivalents are DN50 / 2 inches, DN80 / 3 inches and DN100 / 4 inches. Check the actual connection standard and dimensions.

The key principle is:Choose pipe size against flow, rather than motor power alone. Undersized pipework increases velocity and resistance and can contribute to vibration or cavitation. Larger flows generally need larger pipes.

The main distinction iswhether the pump is submerged or installed above the liquid。

Consider the vertical distance from the liquid level to the pump. If it ismore than about 5 m, review submersible or submerged alternatives. Confirm actual suction limits and liquid compatibility; maintenance access and whether the motor should be kept outside the liquid also affect the choice.

Start with the composition of the liquid and solids.

Begin by measuring these three requirements accurately.

Installation often places the pump below the dynamic water level with clearance above the bottom to avoid sediment. The 1–3 m submergence and 1 m bottom-clearance examples must be checked against the model instructions and well conditions.

Fire pump model codes follow a defined format. For example, XBD7.0/20G-L：

Common letters used in SRM model codes are listed below. Confirm the meaning within the specific series:

Review these possible causes in sequence; the first four are common starting points:

Not necessarily.Oversizing can increase energy use and operating problems.

A pump should operate within a suitable range around its design duty point. Oversizing can move operation outside the efficient range and contribute to excess flow, overload, vibration or cavitation. An undersized pump may fail to meet demand.

The appropriate approach is toselect against actual duty conditions and review an appropriate margin. A 10–20% allowance is an initial discussion point, not a universal sizing rule. Our catalog tool filters records meeting the entered requirements and sorts by excess capacity; the final choice still needs a pump-curve and system review.