Fill Valve

A Fill Valve controls the maximum fluid depth at its outlet by allowing water to pass from the inlet until the downstream depth reaches the configured height. The outlet height can be set anywhere from 0.00 m (measured from the bottom of the nearest solid surface below the outlet) up to the top surface of the fill valve itself. When the water on the outlet side reaches the set level, the valve stops passing additional water. When set to "Unlimited" the Fill Valve functions as a one-way valve: it permits normal flow from inlet to outlet but prevents flow from outlet back to inlet.

A Fill Valve can operate without a signal source or be connected to a signal source. Without a signal source, the valve simply enforces a single desired downstream depth; a common manual setting is 0.75 m. When connected to a signal source the Fill Valve gains separate configurations for the signal-on and signal-off states: the regular setting becomes the configuration used when the signal is on, and an extra setting becomes the configuration used when the signal is off. The valve also includes an option to change the settings of adjacent valves when it changes state; the usual configuration is to leave that option checked.

Connect a Fill Valve to a Depth Sensor to implement automatic control. For example, coupling a Fill Valve to an upstream Depth Sensor set to greater than 0.70 m and configuring the Fill Valve’s On slider to 0.75 m and Off slider to 0.00 m maintains a downstream depth around 0.75 m while preserving an upstream depth target near 0.70 m. Care is required because a Fill Valve trying to maintain a downstream level can drain its upstream source completely; placing a Dam adjacent and upstream prevents the upstream source from being drained when that source falls below roughly 0.50 m.

• Set downstream target heights in meters; 0.75 m is a common practical target for maintaining shallow waterways.
• Use a Depth Sensor upstream (set > 0.70 m) with the Fill Valve’s On = 0.75 m and Off = 0.00 m to maintain downstream water without starving the source.
• Enable the option to change adjacent valves when coordinated valve networks should all switch together.
• Use the "Unlimited" mode when you want a one-way flow without any downstream height limit.
• To prevent upstream depletion, place a Dam immediately upstream if the valve’s operation risks draining the source below about 0.50 m.

A Fill Valve is commonly used in river and dam constructions to keep riverbeds watered during droughts while allowing controlled flow when supply is sufficient.