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Posted by Private on September 13, 2006, 8:23 pm
>
>
>> >> Talked to a few people in the area. Drought here, some wells are
>> >> running
>> >> dry, some are running into water not fit for consumption at this
>> >> point.
>> >>
>> >> In regards to a well running dry, its come to my attention that a pump
>> >> has
>> >>
>> >> no facility for shutting down if there is no water at the head. That
>> >> is,
>> >> continue running and burn up the pump. Is this true?
>> >> --
>> >> Jonny
>> >
>> > We use a pressure switch on our well that will shut off, and remain off
>> > if
>> > the pressure falls below about 5 psi. A little spring loaded lever on
>> > the
>> > side allows you to manually restart the pump when/if that happens.
>> >
>> > These switches are pretty common, and cost maybe $20 at the big box.
>> >
>> > During normal operation, the pressure remans between the 40 and 60 psi
>> > setpoints. If your pressure tank is precharged to slightly below the
>> > low
>> > setpoint,
>> > then the pressure will drop to zero quickly when the well runs dry.
>> >
>> > We've had the misfortune of testing the switch repeatedly during this
>> > drought.
>> >
>> > -Hershel
>>
>> Can't see myself going to the big box store and asking for a pressure
>> switch
>> for controlling/disabling the well pump. A pressure switch normally
>> turns
>>
>> the pump on/off as it is now. Does the disabling switch you're speaking
>> of
>> fall inline electrically with the switch that turns the pump on and off?
>> Or, is it actually a dual purpose switch, one for normal activation of
>> the
>>
>> pump, and for disabling the pump at some low pressure setting?
>> --
>> Jonny
>
> See model FSG2J21M4 at"
>
http://ecatalog.squared.com/pubs/Machine%20Control/Condition%20Sensors/Pressure%20Switches,%20Water%20and%20Air/9013HO0601.pdf
>
>
> This is just a regular well pressure switch with a low
> pressure cut off. They are sold just about any place that carries well
> parts,
> and cost maybe $5 more than the regular switch.
>
> I had to buy a replacement a couple of years ago, think I got it at Ace
> Hardware.
>
> -Hershel
IMHO, I would hesitate to trust this type of switch to reliably protect the
pump from damage caused by running dry. I do have this type of switch
installed but mine prevents motor startup if the pressure falls below about
15 lbs. (normal range ~25-50)
The older technology was to use liquid level controls connected to high and
low level electrodes in the well. This system not only protects the pump
from dry running but also prevents a slow recovering well from causing the
pump to cycle rapidly at the low level cutoff and will not allow the pump to
start until the well has filled to the high level electrode. This system
requires an extra set of wires to run inside the well and also a controller
at the panel. This system is not very elegant and the electrodes must be
cleaned occasionally.
A more recent technology uses a micro controller circuit board added inside
the normal well controller. This controller senses the drop in electrical
current draw by the motor when the load drops due to running with no load.
This control also has a timer to delay the motor from restarting in order to
give the well time to fill. I do not have a link but your pump supplier
should be able to help, or try Google, IIRC they are marketed with names
like pump sentry or pump saver. These controllers are quite elegant and do
not require added wiring so are quite easy to retrofit to an existing
installation, and do not require pulling the pump. IIRC they cost ~$75.
A large (120 gal) pressure tank may also be something you may want to
consider.
Good luck, dropping static levels and low recovery rates are no fun. The
general operating rule is to conserve as much as possible and 'don't get
greedy'.
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