Max. head
The head can be described as the maximum height to which a pump can lift liquid through a vertical pipe without bending or branching. This parameter is directly related to the pressure that the pump produces: 10 m of head approximately corresponds to a pressure of 1 bar (do not confuse this parameter with operating pressure — see more about it below).
The head is one of the key specs for most circulation pumps. Traditionally, it is calculated based on the difference in height between the location of the pump and the highest point of the system; however, this principle is relevant only for units that
boost the pressure of cold water(see "Suitable for"). Circulation pumps for heating and DHW work with closed circuits, and the optimal pressure depends on the total hydraulic resistance of the system. Detailed calculation formulas for the first and second cases can be found in special sources.
Max. power consumption
The electrical power consumed by the pump during normal operation and maximum performance.
This indicator directly depends on performance — after all, for pumping large volumes of water, an appropriate amount of energy is needed. And the power depends on two main parameters — electricity consumption and the load on the power grid, which determines the connection rules. For example, pumps with a power of more than 5 kW cannot be connected to ordinary household sockets; more detailed rules can be found in special sources.
Inlet
The size of the inlet provided in the design of the pump. For plumbing threads (see Connection), the size is traditionally indicated in inches and fractions of an inch (for example, 1" or 3/4"), for flanges, the nominal diameter (DN) of the bore in millimetres is used — for example, DN65.
This parameter must match the dimensions of the mount on the pipe to which the pump is planned to be connected — otherwise, you will have to use adapters, which is not very convenient, and sometimes not recommended at all.
Outlet
The size of the outlet provided in the design of the pump. The value of this parameter is completely similar to the size of the inlet (see above).
Insulation class
The heat resistance class of the insulating materials used in the construction of the pump. The higher the heat resistance — the more reliable the device, the less likely it is to ignite or break the insulation in case of overload or overheating. In addition, powerful performant units can become very hot even in normal operations.
In modern pumps, mainly the following classes of insulation are found:
— B. Materials with a heating limit of 130 °C. They are the most modest option by the standards of pumps. Use binding and impregnating compositions of organic origin.
— F. For this class, the heating limit is 155 °C — the average for pumps. Such insulation uses mainly synthetic binders.
— H. Insulating materials based on organosilicon binders/impregnators. Due to this, their heat resistance reaches 180 °C.
Port-to-port length
The installation length is the distance between the inlet and outlet of the pump, in other words, the length of the segment occupied by the pump in the circuit. This parameter allows you to estimate the amount of space required for the unit, and determine the length of the pipe section that needs to be cut.
