Programming instructions

32 Designer’s Guide
Calsense
Bypass Manifold
A bypass manifold enables the controller to measure low flow readings on a large mainline using the -F
option. It does so by utilizing one (Figure 12
) or two (Figure 13) smaller Flow Meters attached to a large
main. When irrigation or a master valve override starts, the controller uses the bypass manifold to
dynamically manage flow through the appropriate size Flow Meter using the actual flow rate of the
system. This flow rate is monitored continuously and the controller determines which level is optimally
suited to read the flow. Once the appropriate level is determined, the master valves of the other levels
are closed and that level is opened. This process continues throughout irrigation, dynamically opening
and closing the master valves to ensure flow is read across the widest range possible.
When designing a bypass manifold, the smallest master valve in the system can either be normally
closed or normally open to allow for use of quick couplers. However, the other master valves used by
the bypass manifold must be normally closed. Additionally, Flow Meters should be sized smallest to
largest, and the smallest Flow Meter cannot be a saddle-mounted Flow Meter (model FMBX).
Figure 12 - 2-Tier Bypass Manifold
Note: If using a two-tier bypass manifold, the controller’s third master valve and flow meter inputs can
be used to supplement the bypass manifold or to independently manage a non-irrigation point of
connection (not shown), such as those used for wash-downs or other flow monitoring purposes.