Cause:
Unknown but may be related to one of the following items listed below (in no particular order)
Close the Pre calc setup window and see if addressing one of items below fixes the problem.
1. Bad water supply and or pump blocks and nodes
2. If a grid system, there aren't enough gridlines to balance the flow
3. Pre-calc hydraulic reference points were not created and the end-user is relying on the AutoCALC process to generate the ref points
4. Too much flow in the system and the grid can't balance it, therefore it's stuck in a loop
5. Too many head types for one area.
Solution:
1. Erase the nodes and blocks for the pump and city supply. Reinsert the city only and if it makes it into HydraCALC, you can add the pump into stand-alone HydraCALC after the entire AutoCALC process is complete.
2. If you're flowing many heads, follow the advice of #3 and place nodes at each sprinkler head in your remote area but only flow one sprinkler head per gridline, then when you get into the calc file, add your k-factors, densities, areas, and pressures for the heads you turned 'off' in AutoCAD. You can also follow the advice of #4
3. It's always in your best interest to add hydraulic reference points to the calc before you start the process. This makes it easier to find your position yourself in the calc if they're points you've added. Use the RP command to place nodes on your flowing heads and your gridline/gridmain intersections including top and bottom of your riser nipples)
4. If your sprinkler heads demand a lot of flow (ie. k factor of 11.2 or 8.0), change the sprinkler's properties to be a 5.6 k factor head on a 1/2" outlet. Once the calc file has been generated, change the k factor back to its original value in HydraCALC.
5. Redefine heads to be one head type and make sure they were created properly
(i) Close the 'AutoCalc' setup window (ii) In Hcad, replace the sprinklers so ALL flowing sprinklers are the **same** block. (iii) run AutoCalc again. When you get into HydraCALC, fix the density/k-factor/area/pressures to match the original sprinkler values. (iv) When you get back to HydraCAD, make sure to reset the sprinkler heads back to their original blocks. This issue only happens occasionally when sidewalls are involved but has happened with uprights.
