If, however, there has been no draw-off from the tank during the 12 hour
period, the automatic restart at the end of the delay will start the pump and
run it for whatever period you have set on the start timer. The F29 will
sense no flow because the float valve will still be closed. The F29 will then
shut down the pump and again wait for 12 hours before again attempting
to start the pump. Using this technique prevents the pump from hunting on
and off when the tank is full because of slight leakage from the float valve
or pipework. It allows you to set the pump to only operate after a chosen
delay, and if there has been no usage of water, to test the system for
demand by momentarily starting, and only run the pump if there is a
genuine call for water.
The F29 can be programmed to run and stop a pump for set periods of
time. Both the running and stopping times can be set to any value you
choos
e
from 1 minute to 99 hours 59 minutes in increments of 1 minute.
The cyclic running option is highly flexible. The run and stop timers are
totally independent of each other. If a set running and stopping time are
programmed in, the flow switch will run the pump for whatever time it is
set
to and then stop for the time set on its stop timer. If a run time is set
to some value and the stop time is left set at zero, the flow switch will
behave as a one-shot batch controller. On pressing the reset button or
switching the pump on, the pump will run for the set period and then shut
down. It will not then restart until you again press the reset button or
reset the power to the unit. In cyclic running the flow switch monitors the
elapsed time and displays the remaining time on its LCD screen in hours
and minutes.
Cyclic running allows low yield bores to be pumped to their maximum
capacity. A bore pump running under cyclic control can be set to pump
the bore down to a low level, stop and wait for the standing water level
to recover and then repeat the process endlessly. For transfer pumping
applications, cyclic running can be used to automatically top up remote
t
anks without the need for float valves or level control at the tank. It can
also be used for one-shot tank filling. Press the reset button and pump
a set number of hours of water to a tank, and then stop until the reset is
again pressed.
CYCLIC RUNNING
29
