about 8 feet, is that the only factor or should I factor in how
quickly the sump pit fills during heavy rain? Will a 1/2 hp will pump
out considerably more water, faster during a heavy rainstorm or is the
Regardless of rainfall rates, the ground will only pass the water at a
certain rate. You shouldn't see any real difference in the amount of
water running in the sump pit. the 1/3 unit will do just fine. Use
1-1/2" line and a check valve just above the water line to prevent the
line from flowing back into the sump when it shuts off.
I assume that I am misinterpreting what you have written,
Sometimes, our sump intake shows a trickle for weeks at a
time, and sometimes a veritable river.
What did you mean when you wrote "You shouldn't see any real
difference in the amount of >water running in the sump pit"?
I see extremely significant variation...
Thanks for telling me something more.
All the best,
Whew... What was that...? Some Usenet integrity? <VBG> (I
really appreciate it...)
No, we don't have a French drain feeding the sump, and we do
have the variability I had described.
All the best,
The gallons per minute or hour to be pumped and how high it must be
lifted are the two things you need to know. The pump should be rated
in gallons per hour at a given lift. If two pumps will meet the
requirements and one is one third horsepower and the other is one half
horsepower I would go with the slightly heavier duty motor.
An electric motor works hardest when it is starting. To avoid the
motor having to start under the full back pressure of the lift a small
hole is drilled in the pipe just above the connection to the pump and
below the check valve that prevents the water from back flowing into
the sump. This allows the pump to start without having to lift the
full column of water during the start. When a check valve is used in
climates subject to freezing it is important that the piping be
arranged so that no water will be left standing in piping that is
exposed to freezing. It may be necessary to raise the water higher so
that all the piping exposed to freezing will drain to the outside
after the pump stops. In extreme climates a dry well may be needed to
allow the sump to discharge underground. If you are blessed with
terrain that allows underground piping to terminate below your cellar
floor then you will never have to worry about a frozen or fractured
discharge line. That is also a case were a battery driven back up
pump can be fully affective. The back up pump only has to get the
flow started and the siphon affect will do the rest allowing the back
up battery to last a lot longer. If you have to discharge the water
above the level of the sump, like most folks, then discharge it well
away from the building. If you have utility provided water supply and
are at risk for prolonged power outages, such as in areas subject to
ice storms and hurricanes, a water driven ejector; or jet pump if you
will; is a better back up then a battery powered pump.
How fast does the pit fill and how many gallons, how high to pump out.
On Off cycling is hardest on a pump. I would want the smallest that
will just keep me from flooding. I would set the float switch so it
Pat, by definition, the smallest one that keeps you from flooding is
the correct choice. :)
The pump that "keeps you from flooding" is the right pump.
Now, how to choose that size pump.....is the trick question. Only you
know how big your sump is & what sump filling behavior you experience
(worst case). But having a decent sized sump you might be able to get
away with a smaller pump, depending on rainfall beahvior. In Socal we
sometimes get really heavy rain for a day or two (like maybe a
couple / few inches). VERY occasionally (once every ten years?) we
can get an inch in an hour. House rain gutters (5") can be
overwhelmed . On average we get very little rain.
Knowing your sump filling behavior is the best way to size a pump.
If your sump sees input at 1gpm, you dont need a 6000gph sump pump.
If you get a couple gpm...you;re going to need a more capable one.
I wouldn't focus too much on horsepower...mfr's "fudge" the numbers
Look at gph & head (lift)
How quickly does your sump fill up? What pump capacity do you need to
keep the sump from overflowing?
Too large a pump will cycle on/off too frequently.
because people (consumers) tend to put some kind of stock in HP ratings.
And manufacturers tend to LIE their ASSES off about HP ratings.
That's why they removed them from gasoline engines on lawn equipment.
We're still stuck with the LIES on the electric motor equipment. Used
to be (when the HP ratings were accurate) a 3/4 HP motor was about a
foot in diameter and pulled 9 or 10 amps, and would last forever. NOW a
days, they put a 15 HP sticker on a motor the size of a sewing machine
motor that draws 4 amps and lasts about a year.
Because if the pump moves the amount of water to the height they say
it does and it is overwhelmed by the incoming flow they will not have
created a cause of action against themselves in civil court. Fudging
the horsepower makes the pump sound more powerful to a potential buyer
and there are several ways to calculate horsepower. There is only one
way to calculate Gallons per Hour at a given lift.
because gph & head are verifiable by the user.....
and horsepower is close to meaningless for the user, all that matter
is flow rate & head
shop vacs list all sorts of bs horsepower number....like "develops 3
hp peak" or some such nonsense
on shop vac I suggest looking that that amps, not hp
on pumps....... flow & head (a tabular representation of the pump
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