Select a pipe for testing and carefully screw the fitting to the outlet of the submersible pump.
Roll out the pipe on the floor alongside the concrete channel sump, so that it is relatively straight, and check that it does not contain “kinks” (where the pipe twists and folds on itself, obstructing flow).
Carefully lower the pump into the water using a rope tied to the handle (DO NOT support the weight of the pump using either the pipe or the power cord!)
Hold the discharge end of the pipe at a steady elevation between and measure this relative to the water surface in the sump (aim for elevations between 0.5m and 2m above the water level). Make sure there is enough room available to place a bucket under the end of the pipe.
Switch on the pump at the power supply and allow the flow in the pipe to reach a steady rate (hint: hold the end over the sump!)
Using a stopwatch, measure the exact time taken to fill a bucket of known volume. Repeat this several times for the same outlet elevation to reduce the effect of random error. (Flow rate, Q = Volume / Time.)
Repeat steps 1-6 for each pipe diameter and length combination, trialling different elevations each time. Try to cover a broad range, from high flow (short pipe, large diameter, low static lift) to high head (long pipe, small diameter, high static lift).
