Reasonable selection of pump, need to take into account the pump unit, pump station investment and operating costs and other comprehensive technical and economic indicators, so that it conforms to the principle of economy, safety, applicable. Specifically, it includes the following aspects:

1, should choose high efficiency, low noise, energy-saving pump, it is strictly prohibited to choose out of products.

2. The pump should be selected according to the design flow and required head, and the pump output should be reduced due to wear and tear of the pump. The pump can be selected according to the calculated head H multiplied by the coefficient of 1.05 ~ 1.10; The characteristic curve should be selected for the pump whose head decreases gradually with the increase of the flow, so that the pump works stably and works reliably in parallel. And the operation point of the pump should be kept in the efficient operation range, so that both energy saving and not easy to damage parts.

3. When there is no regulation facility in the water supply network, it is advisable to use the speed-regulating pump group or the rated speed pump group to run the water supply. The large water output of the pump unit should not be less than the design flow of water supply in the community, and should be checked in the fire condition.

4. Choose the lifting pump of water tank and water tower to reduce the number of pumps as far as possible. When a single pump can meet the requirements, it is inappropriate to use multiple parallel; If it is necessary to use multiple parallel operation or size of the pump collocation mode, the number of models, models should not be too much, generally should not exceed two types, pump head range should be similar; When running in parallel, each pump should still operate within the high efficiency zone.

5, frequency conversion speed regulation pump (group) design water supply flow should ensure to meet the demand of large design second flow in the domestic water supply system. The power supply should be reliable (double power supply or double circuit power supply); Water pump working point of the persons to be in the water pump characteristic curve (Q - H curve), efficient work areas, and shall not be selected in the Q - H curve on the extension of the design of the adverse working point should be the right endpoint of the water pump characteristic curve of effective section and large water pump water yield, and low head but can meet the requirements of the point, also is the water pump characteristic curve of low efficient area and pipeline characteristic curve of the intersection. The working range of water pump speed regulation can be in the high efficiency section of water pump as far as possible; The speed range should be set between 25% and 100% of the water supplied by the pump. The equipment shall have the function of automatic water level control.

6. The water pump unit of the domestic pressurized water supply system should be equipped with a spare pump. The water supply capacity of the spare pump should be larger than that of a large running water pump.

7. The voltage of the motor matched with the water pump shall be the same, and the power supply mode shall be the same as the state grid power supply mode.