Sump Pump Questions
Thomas Scherer, Extension Agricultural Engineer
| For many homeowners the first line of defense
against water in the basement is a sump with a pump in it. The sump
may be connected to drain tile that drains the footings of the
house, under the entire basement, or just the area where the sump is
located. Many houses have tiling installed only around a portion of
the house. The water that drains into the sump must be removed, and
this is accomplished with a sump pump. |
|
The two basic sump pump models are the up-right (commonly called a
pedestal) and the submersible. Either will work well with proper
maintenance.
The pedestal pump has the motor on top of the pedestal and the pump
at the base, which sits on the bottom of the sump. The motor is not
meant to get wet. The pump is turned on and off by a ball float. One
advantage of this type of pump is that the on/off switch is visible
so the action of the ball float can be easily seen.
Submersible pumps are designed to be submerged in water and sit on
the bottom of the sump. The on/off switch is attached to the pump
and can be either a ball float connected to an internal pressure
switch or a sealed, adjustable, mercury-activated float switch. The
sealed mercury switch is generally more reliable than the pressure
switch.
Either type of pump should have a check valve on the water outlet
pipe so water doesn't flow back in the sump when the pump shuts off.
Water flowing back and forth can cause the pump to turn on and off
more frequently than necessary and decrease the life of the pump.
Some frequently asked questions about sump pumps:
Q. How do you check or test a sump pump?
A. First, make sure the outlet pipe is not frozen shut or plugged
and that it directs water away from the house. Next make sure the
pump is plugged in. Remove the lid (if the sump has one) and use a
flashlight to check if the sump is clean and that the pump inlet is
not plugged. Then slowly pour about 5 gallons of water into the
sump. Try to simulate the speed that water would normally flow into
the sump. Watch the action of the on/off switch and listen to the
pump. Make the pump turn on and off at least twice. If something
doesn't work right, fix it as soon as possible.
Q. Can you burn the pump out if the outdoor pipe is frozen shut,
or will it automatically shut off?
A. Most pumps will not burn up, but they can overheat if left in
this condition. Almost all sump pump motors have thermal protection
built in. If they do overheat you just have to shut them off and let
them cool down. The thermal relay will reset.
Q. What size pump should I have for my house?
A. There is no "correct" size. The horsepower requirement for a
house is determined by the area of drainage connected to the sump,
the depth to groundwater, the depth of the basement, and many other
factors. A 1/3 hp pump is satisfactory for most houses.
Q. Are there any problems with replacing a 1/3 hp pump with a 1/2
hp pump?
A. When used in similar conditions, a 1/2 hp pump will pump more
water and lift it higher than a 1/3 hp pump. Most new sump pumps
will have a chart or graph in the instructions or on the box that
shows the flow versus height of lift for both sizes. The flow is
usually given in either gallons per minute or gallons per hour
(multiply gpm by 60 to convert to gph). The height of lift is given
in feet of vertical lift. There shouldn't be any problem, but where
the flow into the sump is relatively slow there would be no
advantage to using the larger pump. However, in situations where
water flow can become rapid, a 1/2 hp pump may be able to keep up
with the flow where a 1/3 hp pump may not.
Q. Do sump pumps have filters which need to be cleaned or
replaced?
A. Sump pumps do not have filters, but they do have screens or small
openings where the water enters the pump. These can sometimes be
plugged.
Q. Can or should you pump into a sewer drain or basement floor
drain?
A. No, you should not. If you have a septic system, under no
circumstances should the sump be pumped into the basement floor
drain. During wet conditions the drainfield of the septic system is
usually saturated and struggling to handle the normal flow of water
from the house. Adding to it with a sump pump can damage the septic
system. Even if you are connected to a public system the sump should
not be pumped into a floor drain. Putting additional water into the
sewer system can overload the public system, and there may be a
regulation against pumping into it.
Q. Where should the sump pump drain hose be run?
A. Preferably, sump water should be discharged at least 20 feet away
from the house in such a way that it drains away from the house. It
should not be directed onto a neighbor's lot, into window wells, or
onto a septic system drainfield.
Q. Can the average person replace a defective sump pump or does
it require specialized tools or the expertise of a plumber?
A. Almost all sump pumps come with a list of required tools and
directions for installation. It should not be difficult for the
"average" person to replace a sump pump.
Q. How big should the sump hole be? What kind of hole liner
should you use? How much gravel do you put under and around it?
A. Sump holes should be about 2 feet in diameter. This allows space
for the pump and associated piping and to store water between
pumping events (about 15 to 25 gallons). Metal or plastic liners can
be used, but plastic is easier to work with and it the material of
choice. When the sump liner is installed, about 3 to 4 inches of
coarse gravel should be placed in the bottom of the hole. The gravel
forms a solid base for the pump as well as helping to prevent mud
and other debris from clogging the pump.
Q. Should the sump pump be on an isolated electrical circuit?
A. A standard 15-amp, three-prong grounded outlet is sufficient to
handle a sump pump. A sump pump is always in or near water, so it is
best to have an outlet with a ground fault interrupter (GFI).
Q. I don't have a sump in my basement but am concerned about
water leaking in. What can I do?
A. You can push the water to the floor drain, but if water backs up
in the floor drain or drains very slowly a pump is needed. Small
pumps sometimes referred to as "skimmer" pumps are designed to sit
on a flat surface and pump when water on the floor is only 1/4 to
1/2 inch deep. They can often be used with a common garden hose. A
50-foot garden hose run out through a basement window will usually
carry the water far enough away from the house. You can remove more
water by taking the cover off the floor drain and placing the pump
in the drain bowl -- these pumps are usually small enough to fit in
the bowl. In emergencies where electric service is off, these pumps
can be powered by a small gasoline generator. |
|
What is a sump pump system?
Replacing or installing a sump pump
Sump pump buying options
Battery Backup Sump Pumps: Should You Have One?
Common Reasons Why Sump Pumps Fail and
How to Avoid
Purchasing A Good Quality Sump Pump
Sump Pump Installation for Do It Yourselfers
Frequently Asked Questions About Sump Pumps
|