HAMMER error: "Zero initial head from pump (turbine). Change at least one of the heads at the pump ends of the adjacent pipes."

Product(s): HAMMER
Version(s): CONNECT Edition, V8i
Area: Output and Reporting


How can a user resolve the following user notification?

"Zero initial head from pump (turbine). Change at least one of the heads at the pump ends of the adjacent pipes."


First, check the transient calculation options and ensure that "Specify Initial Conditions" is set to "False" unless you are in a very rare situation in which element properties need to have user defined initial conditions (instead of the initial conditions computed by the steady state/EPS solver). If it is set to "true", the problem could be due to a mismatch between the pump user defined initial conditions and the adjacent pipe initial conditions. 

If you already have this option set to "false", try the following: First, compute the initial conditions. Next, double-click on "Base Calculation Options" under the Transient Solver. Change the item "Specify initial conditions?" to True. Next, go to Tools > Copy Initial Conditions. This will copy the data for the initial conditions from the earlier step into the element properties.

Now, open the properties for pipe downstream of the pump specified. Find the items "Hydraulic Grade (Initial Start)" and "Hydraulic Grade (Initial Stop)" (note that these are only available when "Specify initial conditions" is set to True). Set both the start and stop to a value 0.01 feet above the value already there. Now edit pipe immediately downstream of this pipe set just the start HGL value to the same value as the stop hydraulic grade in the previous pipe.

Finally, open the pipe flextable. Find the column for "Darcy-Weisbach f (Initial)". If you do not have this column, use the Edit button to add this field to the flextable. Right-click on the column edit and select Global Edit. Set the value of this field. It will very from model to model, and you may want to review the results after computing. A value of 0.012 is a decent assumption to start. Now when you compute the transient solver, the error message should be gone.

You may also want to upgrade to the latest release of HAMMER as well, as improvements to the calculation solver may allow the model to be computed in these situations.