How pumps work


Rain Sensors? In Most States It's The Law!

Most states and/or cities in the U.S. nowincreased placement options offset the cost.
require rain sensors by law. They are simpleMost wireless units come with by-pass
to  install  and  pay for themselves quickly.switches  built  into  the  device.
For this reason every lawn sprinkler systemSome digital controllers also offer by-pass
should have a rain sensor. The rain sensoroptions for both wired devices and wireless
determines whether or not enough rainfall hasrain sensors. No matter the type of rain
occurred in order to skip an irrigationsensor type that you choose, all rain sensors
cycle.offer many advantages over not adding this
detector  to your automatic sprinkler system.
There are 3 basic types of rain interrupters.
They all serve the same purpose: keeping yourSome of the immediate and long term benefits
system from over-watering the turf or yourinclude:
garden.  How  does  it  do  that?
- Saves Money. Whether you pay for city water
The electrical connection between the sensoror spend electricity running a pump, the
and your sprinkler system controller ismoney you save over time will more than pay
interrupted when a certain amount of rainfor  the  rain  sensor.
triggers the device. The sensor breaks the
electrical connection so that electricity- Extends Sprinkler System Life Span.
cannot flow to either the sprinkler valves orSprinklers are made up of gears and other
to a pump start (if your system is on a wellparts that move. The less the sprinkler parts
without  a  pressure  tank).are  used,  the  longer  they  last.
One type breaks the connection by weighing- Protects Water Resources. By limiting the
the water in a rainfall collection cup. Theover use of your sprinkler system, rain
problem with this type is that leaves,sensors reduce excess water run-off that
sticks, or the occasional lizard will findcarries fertilizers and pest control
its way into the collection cup and thereforechemicals  into  our  shared  water  supply.
turning  off  the  system.
- Conserves Water. Less water is wasted when
The next type uses electrodes to determineless supplemental water is needed for your
how much water is in the collection cup. Thisturf  and  in  your  garden.
kind of rain sensor device also has a system
problem of collecting things other thanHow much money can you save with a rain
rainfall  in  the  collection  cup.sensor device? It will vary based on your
water source (city, re-claim, or well) and
The expansion disk type seems to be the mostwhere you live (water costs, electrical rate,
popular. This kind of sensor does not use aclimate).
collection cup; instead rainfall causes cork
disks to expand. This device uses a pressureHere is one example that demonstrates the
switch to break the electrical connection.benefits listed above: Seminole County,
These can be adjusted in increments of ¼"Florida.  System  Description:
to the desired rain fall setting. These
adjustments can be configured to kick in fromIntended to sprinkle a 1/4 acre of turf
1  to  a  1/2"  of  rain  has  fallen.calibrated to precipitate a half inch" of
water  every  time  the  system  runs.
The most important aspect of installing a
rain sensor is where to place it. It should- This schedule would equal 6,788 gallons per
be installed in an area that is unobstructedirrigation  cycle.
by trees, roof over hangs, or anything else
that might block rain from getting to the- This system (on City Water) pays $2.30 per
sensor.thousand  gallons.
If it is a wired sensor, placement is- Every time the rains sensor interrupts a
generally near the sprinkler controller. Thesprinkler  cycle,  you  would  save  $15.61
wires should be connected inside the
controller's valve wiring panel. This allowsAccording to a recent study in Florida, the
for easier electrical trouble-shooting of theuse of a rain sensor device averaged a 45%
system as the sensor can be easilysavings in water for single-family
disconnected.residential water usage. The next time you
see a sprinkler system running in the rain,
Year by year, as technology improves, FMyou now know it doesn't have to be that way.
sensors have become more popular. AlthoughRain sensors save money, save our environment
they are more expensive than the wiredand save water.
devices, the ease of installation and



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