I'm a new user and got this WaterGEMS error "Unexpected Reverse flows calculated" at one of the pumps. In the capture below, the highlighted pump are the one causes this error with its pump pattern attached. I think the pump in Watergems is automatically installed with a check valve which protect from reverse flow, so I wonder why still I got this reverse flow on the pump link and any idea where I may check to make this work?
Thanks for the help.
Please check if the downstream pipe is properly selected. You can view this in the pump properties. If the property field for Downstream Pipe is incorrect, you can reverse this in the properties too. The following link has information on this: How do you change the direction of the downstream pipe for valves and pumps?
In the snapshot you provided I can see that you are getting "Network Unbalanced" notification too. This is an indication that there is an error in the model. Any red user notifications will need to be resolved before the results will be correct. See the below link for details on how to troubleshoot this;
Troubleshooting the Network Unbalanced or Cannot solve network hydraulic equations user notification
Try resolving these issues and see if there are problems.
Let me know if this helps.
Bentley Technical Support
Yes the pump towards to the correct downstream (you may also confirm this by checking the pump symbol pointing to the right dirction in that snapshot). Thanks for pointing out the unbalanced notification, actually this is exactly the reason I brought up the pump reverses flow question.
I figure the pump flow reverses could be the reason to cause this unbalance. As you may see in the snapshots below, that pump is acting okay until 7:00 clock and that's the time the model got the unbalanced error.
Please check the pipes downstream to the pumps and make sure that they are not closed or causing reverse flow towards the pumps. Additionally, I saw two pipes connecting the middle two pumps. Is this as per your configuration?
What are the circled pipes for? Do they carry flow downstream? What happens if you remove them?
In the above snapshot you can see the 4 pumps in parallel. There are no additional pipes connecting the pumps on the inside. I think these pipes could be causing the reverse flow in this case.
If everything is set correctly, and you see such results we would need a copy of the model to check. Please share the hydraulic model files as per this article: Sharing Hydraulic Model Files on the OpenFlows | Hydraulics & Hydrology Forum