What Does Maximum Flow Mean On A Pond Pump Box?
This is a good question because maximum flow has misled thousands of people
into buying a completely inappropriate waterfall or pond pump. In a real pond situation where a waterfall is wanted then
maximum flow is NOT the volume the pump will deliver to the waterfall.
Maximum water flow for any submersible pump (in fact any kind of centrifugal
rotating pump) occurs when no pipe (or anything else) is attached to the
pump . Of course in a pond there is almost always a need to attach a pipe to
deliver water to a water fall maybe or at least a pond filter sitting above the
ground. It is a basic physical characteristic of a submersible pump made for
ponds that if the pump must lift water above the pond surface then the actual
flow will drop and the flow will continue to reduce as the height to which water
is pumped increases. A point will thus be reached where water flow stops all
together (this is called maximum head ... see more).
The size of electric motor and its design in terms of efficiency determine
the maximum flow for any pump. In other words the more energy or power driving
pump then the more water mass or volume that pump can move. Since this power
(motor size) is fixed or constant in pond pumps then the energy available
is also fixed. This is why as pumping height is increased then the mass of water lifted
to that height must be reduced to balance the energy supplied.
Why Is Maximum Flow Useful?
If the term maximum flow for a pond or waterfall pump has any practical use
then it is simply as a means to try to compare pumps in general. 3 pumps within the same model series
e.g. Hozelock Cascade pumps with maximum flows 1000, 2000 and 3000 then you immediately know
that the power to deliver these different amounts of water must be greater so
the larger pumps in general can be expected to pump larger volumes at similar practical
heights because the energy or pump power is higher. What you don't know is
how much each pump will deliver in any practical situation and to make matters
more complicated not all pumps having the same maximum flow behave in a similar
way. See this article on comparing pond pumps .
What Do The Pump Products Model Names Normally Mean?
Maximum flow is a useful way of naming pump models within the same pump series
or range. For example the Hozelock Titan range has pump models within the
product series as follows ...
Titan model 2000
Titan model 3000
Titan model 5500
Titan pump 8000
Titan pump 12000
Titan filter pump 15000
The Hozelock Titan range of pumps are used mainly to supply pond filters or
waterfalls rather than fountains or basic water features. The numbers in the
product range shown above refer to actual approximate water flow rates with no
pipe attached ... in other words approximate maximum flow. At 1 metre head the
flows are shown below and you can see where there is room for mistakes by not
understanding the meaning of pump flow terms...
Titan filter pump 2000 flow at 1 metre = 1000
Titan filter pump 3000 flow at 1 metre
= 2200 lph
Titan filter pump 5500 flow at 1 metre = 4500
Titan 8000 flow at 1 metre = 6800 lph
Titan 12000 flow at 1 metre = 9000 lph
Titan 15000 flow at 1 metre = 11000 lph
To convert lph to gallons per hour or gph divide litres per hour by 4.54