| Product(s): | HAMMER |
| Version(s): | CONNECT Edition |
| Area: | Calculations |
When attempting to compute a transient simulation in HAMMER, it fails with the following user notification:
"The steady flow must be greater than the Flow Tolerance calculation option. Run the Copy Initial Condition tool, set the Specify Initial Condition calculation option to true, and manually enter the nominal flow and head."
This can occur for a pump if the pump status is set to On, the transient pump status is set to "constant speed" or "shut after time delay", yet the calculated flow in the initial conditions is zero (or more specifically, the flow is so small that it is below the "Flow Tolerance" transient calculation option, which is used to determine the threshold of what is considered "zero" since small numerical noise can sometimes occur).
This situation could happen for example if the pump cannot overcome the head that is already in the system, or if there is no other boundary condition or demand downstream. If this pump should be off in the initial conditions, change the initial status to Off and set the transient pump type to "constant speed". If the pump should be on, you may need to investigate why it is not able to pass any flow. Examine the status of downstream elements and look for physical connection issues. See more here: User Notification: "Pump cannot deliver flow or head"
Be sure to also check the "Specify Initial Conditions" transient calculation option, which should be set to "false" if you want to use the calculated initial conditions. (see more below)
User notification: "Pump Efficiency must be between X% and Y% inclusive."
"Specify initial conditions" calculation option and "Transient (Initial)" element properties