System disconnected (pump and PRV)

Hello Nastassja,

There are several user notifications with your model. However, I don't see the system disconnected user notifications at 23.10 and 31.20 hours for the "P1 Max Day EPS 24 hr" scenario. I have tested this in WaterGEMS 10.03.01.08. Here are my observations;

Upon validation I found that there are two actions which are referring to PMP-501 which is inactive in this scenario. Actions A1264 and A1265 are referring to the On and Off status of PMP-501. I deleted those actions and controls for now to proceed with running the simulation. If you have setup a control which is used in a scenario where the element associated with it is active then you can make use of "control sets" in which you can choose which controls to execute for different scenarios. See the article below for details on this;

Creating Controls - Conditions, Actions, and Control Sets (CONNECT Edition and V8i SELECTseries 6)

After resolving the controls I ran the model and have the following user notifications;

"Unexpected reverse flows calculated. Check for reverse flows through pumps and valves; messages for specific elements follow."

The above user notification is a warning to check for other user notifications for specific elements. Similar errors like "FCV has reverse flow.." are occurring for FCV-3, 4, 6, 7, 8, 9, 10 and 11. I checked for FCV-7 in this case at time 25.40 hours and it seems that the source connecting to FCV-7 i.e reservoir MM-7 is receiving water (reverse flow) due to higher hydraulic grades of its upstream sources such as reservoir MM-1 which is at an elevation of 5135 ft and the PMP-500 for which the downstream hydraulic grade at J-502 is 5123 ft. Due to these higher hydraulic grades upstream the reservoir is unable to supply but rather receiving water. WaterGEMS will try to balance the energies at the sources at every time step during simulation based on assumed hydraulic grades at boundaries like reservoir and demands.

Please check similarly for other FCV also. This is most likely due to the FCV's not functioning properly as per the initial flow setting for the FCV's. Apart from the above user notification, there are errors of "FCV cannot deliver flow". I think you had a similar issue in the past with reverse flows through pipes with check valves and FCV's which was answered by Sushma and Jesse in the below post;

Reverse flow through check valve on pipe.

They have also provided some troubleshooting steps and articles to resolve this issue. Please try those options.

Additional user notifications include,

"Junction disconnected.." which can be resolved by following the troubleshooting steps provided in the article: System Disconnected or Junction Disconnected user notification messages

"Network Unbalanced" which can be resolved by following the troubleshooting steps provided in the article: Troubleshooting the Network Unbalanced or Cannot solve network hydraulic equations user notification

I would suggest to go through your setup once again with a clear objective of what kind of results you wish to simulate. If you want to control FCV's in an EPS run it should be ensured that the flow available upstream is always higher than the flow setting of the FCV. Similarly, PRV's also need to have a higher hydraulic grade or pressure upstream to ensure that pressure is reduced effectively downstream.

Let me know if this helps.

Yashodham,

I may have accidentally uploaded the model after I turned PRV-228 inactive. When that PRV is active, that is when I see the user notifications that I do in the Intra Trial status messages.

I changed the operational alternative to the base operational (without PMP-501) and resolved the validation errors. 

Responding to the FCV cannot deliver flow. This model was set up (by someone else) with reservoirs and FCVs to simulate flow from master meters. These locations are meant to supplement flow delivered by the pump. The FCV setting is set to the maximum amount of flow that the town is allowed to pull from these locations to ensure we do not overtake. This is why I am not concerned with this particular user error. 

Each of the master meters has a check valve to prevent reverse flow. This is the part I am struggling with. I cannot seem to get that error to go away. 

EDIT: There was a PRV setting that was too low in the system that was causing the error. Having since increased the PRV setting I don't have anymore user notifications of concern. I found it when I noticed that there was no flow going into the pipe upstream of the PRV.