I am having some trouble with model.
At first, I was getting an unbalanced system. I did the walkthrough on how to check and fix an unbalanced system. We updated the controls, elevations, and pump curves.
Right now the Model is getting three errors.
I am getting reverse flow through PRV-5. I have been trying to fix this but I think there is something going on with the pump near it that I can't figure out how to fix. The other issue is that I am getting negative pressure in my system. The wells should be producing more than enough water to have descent pressure. I have already checked with the engineer and the client to make sure the set up is correct at this specific Tank.
I am working with the newest Watergems version and Engine used was WaterGEMS 2.00.12.
Hello Mark,
First, double-check that the downstream pipe for the PRV is correct.
Otherwise, the issue may be related to the disconnected demand nodes message you are also getting. WaterGEMS is a demand-driven system, so all demands must be satisfied to have valid results. If there are demands not able to be satisfied (because a tank is empty, a pump is off, a valve is closed, etc.) this will lead to errors in the calculation, including the possibility that WaterGEMS will try to force flow the wrong way through the valve. Resolving the disconnected demand nodes message will hopefully resolve the issue.
Regards,
Scott
I suspect that something that is supposed to be feeding the pressure zone with the tank is not running.
Plot tank HGL vs. time to check that.
If HGL is dropping rapidly, check on the pumps/reservoir that is supposed to be feeding that zone to make sure they are connected and operating.
I took the check valve off the pipe going from the system into the Tank-3E1. This corrected the problem disconnected demand nodes and the reverse flow at the PRV-5. Now it is saying another PRV-11 has reverse flow but I don't have a check valve set up in there.
See if you are getting a Network Unbalanced user notification. If so, you can try making some adjustments to the calculation options to see if that helps with the issue.
Otherwise, we would need to see a copy of the model.
Some practical tips.
Make sure the tank is at a very low level (tank essentially empty), if the PRV opens. Put the PRV target HGL near the bottom of the tank. The PRV should only open when, e.g. there is a large fire in the lower zone that has drained the tank.
Make sure the pump does not run when there is flow through the PRV. Otherwise, you'll be just pumping in a circle.