Programming instructions

Designer’s Guide 27
Calsense
Flow Meters
Tee Type Flow Meter (model FM)
The Calsense Flow Meter enables Calsense ET2000e Irrigation Controllers to measure the flow rate of an
irrigation system, making it an important management tool in detecting mainline breaks, broken risers,
and closed or stuck valves. It is installed in the main line after the water meter or backflow preventer.
The master valve can be installed on either side of the Flow Meter.
When installing a Flow Meter, the mainline pipe is typically sized down to accommodate the fitting of
the Flow Meter. The intended direction of the flow is indicated by an arrow on top of the Flow Meter.
There must be free, unrestricted pipe of the same size as the Flow Meter, with a length of at least 10
times the Flow Meter size upstream and 5 times the Flow Meter size down-stream of the Flow Meter
tee (Figure 10
). This applies to distance from any valve, pipe fitting, water meter, or backflow device.
The Flow Meter should be easily accessible, housed in a rectangular valve box marked 'FM'. There
should be six to eight inches of pea gravel beneath the Flow Meter in the valve box. Additionally, the
length of #14 gauge (AWG) wire connecting the Flow Meter to the ET2000e Irrigation Controller must
not exceed 2,000 feet.
Figure 10 - Tee Type Flow Meter Installation
Insert Type Flow Meter (model FMBX)
The Calsense Insert Type Flow Meter is designed to be used for mainline pipes ranging in size from 3 to
18 inches. It is mounted to the pipe using a pipe saddle or welded-on threaded fitting which are not
included (Figure 11
). It is constructed of brass and bronze hardware and is provided with a bronze 2-inch
NPT externally-threaded hex adapter for mounting. The accuracy of flow measurement is highly
dependent on proper location of the sensor. It should be positioned on top of a horizontal pipe and
located along the pipe where 10 times the pipe diameter upstream and 5 times the pipe diameter
downstream of the Flow Meter provide no flow disturbances. There should be no pipe bends, fittings, or
valves within these minimum distances.