Sump pump
From Wikipedia, the free encyclopedia
A sump pump is a pump used to remove water that has accumulated in a sump pit. A sump pit, commonly found in the home basement, is simply a hole to collect water. The water may enter via perimeter drains funneling into the pit, or may arrive because of rain or because of natural ground water, if the basement is below the water table level.
In some cases, a sump pump is used when a lower floor is below the municipal sewer lines, to pump greywater or blackwater waste from that floor to the sewer lines.
Sump pumps are installed particularly where basement flooding is seen as a problem, but are also used to ameliorate dampness where the the water table is normally above the foundation of a home. Sump pumps send water away from a house to any place where it no longer presents a problem, such as a municipal storm drain or a dry well. Older properties may have their sump pumps connected to the sanitary sewer, but this is frowned upon now (and may be against the plumbing code) because it can overwhelm the municipal sewage treatment system. Sump pumps are usually hardwired into a home's electrical system, and may have a battery backup. Some even use the home's pressurized water supply to power the pump, eliminating the need for electricity. Since a sump pit may overflow if not constantly pumped, a backup system is important for cases when the main power is out for prolonged periods of time.
There are generally two types of sump pumps: pedestal and submersible. The pedestal pump's motor is mounted above the pit, where it is more easily serviced but also more conspicuous. The submersible pump is entirely mounted inside the pit, and is specially sealed to prevent electrical short circuits.
[edit] Components
Modern sump pump components in the United States are standardized. They consist of::
- A plastic or metal canister forming a sump liner, approximately 2 feet (0.6 m) across and 2 to 3 feet (0.6 to 1 m) deep, 15 to 25 US gallons (60 to 100 L);
- A sump pump, either 1/3 or 1/2 horsepower (200 or 400 W), either battery or electrically powered (or both);
- A set of pipes, typically 1.5 inch (38 mm) PVC, that are routed from the pump, through a check valve, and out of the house;
- A check valve that allows water to flow up and out through the pipes, so when the pump turns off, the water in the pipes doesn't flow backwards back into the sump;
- A sump cover so that mice, cats, etc., don't fall into the sump and drown;
Optionally, some homes (especially ones with finished basements) have a secondary battery-powered sump pump in case the first pump fails. Setting up a battery backed-up secondary pump involves purchasing and installing the following components in parallel with the above others:
- A battery-driven 12 V sump pump with its own water level sensor, piping, and check valve (since check valves fail)(the pipes usually join after the check valves);
- A typical lead-acid car battery (may alternately be a marine deep cycle battery but these are more expensive);
- A typical trickle-charge car battery charger available at any automobile parts store.
[edit] Maintenance
Sumps and sump pumps need to be maintained. Some cautious people might say "every year", but every 4 or 5 years is usually enough. If you live in very sandy or muddy area where your pump runs a lot, it might make sense to do this every year.
The goal is to clear out the dirt, gravel, and sand from the sump. They are carried in by the water, and accumulate. This drastically shortens the life of the pump and can jam it up completely, burning it out. It can also jam up the check valve, preventing it from opening, and thus preventing water from being pumped out, which again can burn out the pump. So, a burned out pump might be really caused by a clogged check valve, a clogged pump, both, or just a very old sump pump (though these tend to be pretty long-lasting if properly maintained).
The cleanout is simple - scoop out the dirt. The following steps make this easier:
- If you have a battery backup unit: unplug the main sump pump and trigger the battery back up unit to test that it works. Re-plug in the main sump pump again.
- Run the main sump pump to make sure it works, too. Let it run until as much water is possible is out of the pit.
- Unplug the sump pump so you don't get electrocuted.
- Have a small garbage can handy and a small plastic cup you can use as a scoop.
- With a screwdriver, disconnect the pipe below the check valve so you can lift the sump pump out of the pit, and do so.
- Hold the garbage can under the check valve and press up with your finger or a screwdriver to let the water out into the garbage can. There may be a lot. If you can't open it, it's installed upside down, jammed up, or broken.
- Disconnect the top of the check valve and wash it under running water. There may be some dirt in it, or maybe not.
- Reconnect the check valve so you don't lose it.
- Lie down on your stomach on the floor, roll up a sleeve, and scoop up dirt from the bottom of the sump into the nearby garbage can. Clean all the dirt out of the sump pit. There may be quite a lot of it. If you get down more than 3 feet (1 m), it's probably a good idea to stop, though, since that probably means there's no bottom to your sump pit. You can also use a screwdriver to feel through the muck to find the bottom.
- Dump the dirt, sand, and gravel you get out of the sump outside somewhere, it's just clean dirt.
- Put the pump(s) back into the clean sump, reconnect the pipes, and make sure the float has free motion to lift up so the pump can turn on.
- Plug it back in and test it by lifting the float, or by filling the sump with water from a hose.
[edit] Resources
- "Sump Pump Helps Keep Water Out", North Dakota State University Extension Service, June 14, 2005
- Thomas Scherer, "Sump Pump Questions", North Dakota State University Extension Service
- "Sizing Up a Sump Pump" (pdf), University of Illinois Extension
