unbalancing due to 1 pipe

[Vladyman]

I am preparing a mode
The model run ok, balances after 32 iteartions.
When I add 1 pipe connected to one node with demand zero, then the model does not balance. I increase to 200 iteration but still not working. WHat copuld be the problem?

[Patrick Moore]

Vladimir,

It appears, something is causing the flows in that pipe to have difficulty converging. EPANET starts every pipe at 1 ft/s velocity so even a pipe with no demands has a non zero flow in it initially.

Try adjusting your simulation options as follows to get convergence.

General Tab:
Trials: 200
Accuracy: 0.001
Unbalanced: Continue
Extended Run: 50
(click if need larger image)
Simulation Options - For Convergence.jpg

Advanced Tab:
Status Check Frequency: 2
Max Status Check Iteration: 10
Relaxation Factor: 0.6
Damping: 0.01 (i.e. at 10X your accuracy on the general tab)
(click if need larger image)
Simulation Options - Advanced.jpg

This should help it converge and resolve your issue.

If it still fails to converge make sure to set your report options to show a full status report and warning messages as this will tell you more about why it is having issues:
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Full Report with Warning Messages.png

If you still have difficulties please let us know.

Patrick Moore