Maximum performance
The maximum volume of water that the device can pump in a certain amount of time. It is one of the key specs of any pump because characterizes the volume of water with which the device can work. At the same time, it does not always make sense to pursue maximum performance — after all, it significantly affects the dimensions and weight of the unit.
Some formulas allow you to derive optimal performance values for different situations. So, if the pump is designed to supply water to water intake points, its minimum required performance should not be lower than the highest total flow rate; if desired, a margin of 20-30% can be added to this value. And for sewer models (see "Suitable for"), everything will depend on the volume of wastewater. More detailed recommendations for choosing a pump depending on performance can be found in special sources.
Maximum head
The maximum head generated by the pump. This parameter is most often indicated in meters, by the height of the water column that the unit can create — in other words, by the height to which it can supply water. You can estimate the pressure created by the pump using a simple formula: every 10 m of head corresponds to a pressure of 1 bar.
It is worth choosing a pump according to this parameter, taking into account the height to which it should supply water, as well as adjusting for losses and the need for pressure in the water supply. To do this, it is necessary to determine the difference in height between the water level and the highest point of water intake, add another 10 to 30 m to this figure (depending on the pressure that needs to be obtained in the water supply), and multiply the result by 1.1 — this will be the minimum pressure required.
Max. pressure
The highest pressure that the pump is capable of creating during operation. This parameter is directly related to the maximum head (see above); however, it is less obvious, and therefore, it is indicated rarely.
Maximum liquid temperature
The highest temperature of water at which the pump is capable of operating normally. Usually, in most models this parameter is 35-40 °C — at high temperatures it is difficult to ensure effective cooling of the engine and moving parts, and in fact, such conditions are rare.
Float switch
The presence of a float switch in the design of the unit.
The operation of such a switch is based on a sensor in the form of a float, which determines the level of the pumped liquid. At the same time, such a sensor can perform several functions at once. The main one is the protection of the pump from dry running: when the liquid level drops critically, the sensor turns off the pump, preventing air from entering the line and helping to save energy. In addition, the float can be used as an overflow sensor (warning of a critical increase in the liquid level), and in some models also as a general-level sensor (reporting the actual amount of liquid).
Outlet size
The thread size for connecting a hose or pipe to the pump outlet. If there is a branch pipe with an external thread in the design, the size is indicated for it; if not, for the internal thread of the inlet.
Anyway, the dimensions of the pump outlet and the mounts on the hose/pipeline connected to it must match — otherwise, you will have to look for adapters. This size is specified in inches and fractions of an inch.
This parameter is relevant primarily for surface models.
Maximum power
Rated power of the pump motor. The more powerful the engine, the higher the performance of the unit, usually, the greater the pressure, suction height, etc. Of course, these parameters largely depend on other features (primarily the pump type, see above); but models similar in design can be compared in terms of power.
Note that high power, usually, increases the size, weight and cost of the pump, and also implies high costs of electricity or fuel (see "Power source"). Therefore, it is worth choosing a pump according to this parameter taking into account the specific situation; more detailed recommendations can be found in special sources.
Country of origin
Country of origin of the brand under which the pump is marketed.
There are many stereotypes related to how the origin of goods from a particular country affects their quality. However, these stereotypes are unfounded. Firstly, this paragraph does not indicate the actual place of production of the unit, but the "homeland" of the trademark (or the location of the manufacturer's headquarters); production facilities may be located in another country. Secondly, the actual quality of the product depends not so much on geography, but on the organization of processes within a particular company. So when choosing, it is best to focus not so much on the "nationality" of the pump, but on the overall reputation of a particular brand. And paying attention to the country of origin makes sense if you fundamentally want (or do not want) to support a manufacturer from a certain state.
