WaterGEMS: Inlet Valve throttle settings

Hi,

I'd like to ask for some assistance in modelling a throttle valve on a tank.

I've got a model with some tanks in it, and it had been running fine up until now, but as soon as I try to model a float valve with the "Inlet valve throttles?" setting, the model gives me the error "Engine calculation failed. Please see user notifications for possible causes."  The user notification says "41110: Cannot solve network Hydraulic Equations."

The tank settings when the model was running were the following:

Tank fills from top?:             True

Level (Inlet Invert)(m) :        4

Inlet Valve throttles?:           False

I then changed the settings to the following and re-ran the system which then gave me the aforementioned error message. I did not add/delete any elements:

Tank fills from top?:                                True

Level (Inlet Invert)(m) :                            4

Inlet Valve throttles?:                              True

Discharge Coefficient:                            0.8

Level Inlet Valve Starts to close(m):    3.5

Level Inlet Valve Fully closed(m):         4  

Valve Type:                                                 Butterfly

I've used the "Validate" tool, and that returned the message "No problems were found". I also used the Network Navigator to search for "Find initially isolated elements", "Pipes missing nodes" and "orphaned nodes", none of which returned any elements.

Could I ask for some assistance with troubleshooting this error?

Thanks very much.

Kind regards

Stefan