You are currently reviewing an older revision of this page.
I am getting ERROR 171: <Pump Curve Name> has invalid or out of sequence data while using the SWMM engine. Why is this and how do I fix it?
Look at the pump curve referenced in the message and make sure that all the flow values are in increasing order and that all the head values are in decreasing order. If you have head values that are the same somewhere in your curve please make sure that you very those values by a small increment or you will recieve the same message. For example, if you have a head value that is 120 ft. and your next value is also 120 ft. make the first value 120.01 ft. and the second value 120.00 ft. This will ensure that you have still have decreasing head values while having little to no variation in head. If you can't see the two extra decimal places at the end of the numbers you can adjust the units and formatting in order to do so. You can find directions on how to do this in the "See Also" section below.
Adjusting the units and formatting