I am modeling a pump station (set as VSPs in parallel, lets name them Pump Set 1) that is fed from an above-ground storage tank by gravity and pumps to a distribution system. I put the pump controls on the pump station discharge pressure and it is working as expected.
My above ground storage tank is fed by another set of VSPs (lets name them Pump Set 2) (different location) that pump from a chlorine contact basin (with control set on HGL on the chlorine contact basin, to maintain) and that is working as expected also.
Depending on the flows in and out of the storage tank, the storage tank can become full. In this case, I would like to set up controls that would turn off the chlorine contact basin pumps and activate another set of VSPs in parallel (Pump Set 3) (not the two sets already mentioned) to pump directly from chlorine contact basin to injection wells.
How can I do this?
WaterCAD does not seem to like it when I set Pump Set 3 pumps (VSPs with control on chlorine contact basin) to OFF at time zero of my EPS since there are two different pump sets with the same control nodes even though the Pump Set 3 is OFF initially. I would like the two pump sets to alternate based on my condition (if storage tank is full, Pump Set 3 to take over, if storage tank is not full, Pump Set 2 to pump to storage tank).
Hello Parsa,
What error messages do you receive after you set controls for Pump Set 3? OR is it unable to solve hydraulic calculations kind of error? More details about it would be helpful.
Does the below situation describes your case as well, please go through it and let us know.
Modeling multiple VSPs where only one turns on at a time
If not then please elaborate the issue, if required you may upload model files as well.
Regards,
Sushma Choure
Bentley Technical Suppport
Hi Sushma. I uploaded the model. I get a "Network Unbalanced" message and my controls are not working.
Here is a schematic of my system:
Here is the system description and what I would like to achieve:
Here is how I wrote the controls:
I took a look at the model. Part of the issue may be with the controls. First, there are controls to turn PMP1 and PMP2 on based on some conditions. However, they cannot turn on because of the setting of the GPV GPV-Sump-EffBox. The GPV is off at all time steps, meaning that the pumps will be unable to pump into the downstream tank.
The other pumps (BW34, BW35, and BW36) are a part of this control as well. As these are associated with the tank CCB Wet Well, be aware of how the controls will be expected to work here. This link has details. However, the GPV feeding this tank may also have an impact on what is happening with the controls.
Related to the GPV, there is a control that turns this valve off, but none that will actually turn it back on. If there should be a control that turns this on, it should be included as well. If there is no control to
Overall, I would start with reviewing the controls and the general setup of the system to assure that everything is in order.
Scott