Guide to Different Types of Sump Pumps for Water Removal from Buildings
This article describes the different types of Sump Pumps, and describes how sump pumps should be installed, inspected, and maintained.
We describe types of back-up sump pumps including battery backup sump pumps and water powered sump pumps and we list sump pump and backup sump pump equipment suppliers.
We include specifications on pumping capacity, battery life, water consumption and other sump pump characteristics.
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A sump pump is normally installed in a pit at the low end of a basement or crawl space floor or in another location where water needs to be removed such as in a boiler pit or an outdoor well pit.
This article describes four types of pumps used to remove water from buildings or to lower water below a basement or crawl space floor to reduce the chances of water entry.
Submersible sump pumps, such as shown in the photo at left, use a motor housed in a water proof enclosure and a separate float that turns the pump on and off.
The sump pump float contains a position-activated switch and is connected to the submersible pump by a flexible wire. Some submersible sump pumps, such as the one shown here at left, use other types of float switches.
The submersible sump pump motor is capable of working when entirely under water.
A submersible sump pump uses a float switch intended to turn the pump on when ground water rises in the sump pit (or flows stupidly across your basement and into the pit) where it is discharged to a storm drain or the property surface.
Watch out for debris or wiring in the sump pit that block movement of the float switch - your sump may fail to turn on.
Pedestal sump pumps, such as shown in the photo at left, use a motor atop a pipe inside which the pump turns a shaft which operates the pump impeller. The pump impeller is located in a bottom pedestal which is under-water.
You'll notice that the electric motor that powers the pump impeller is mounted on top a tall shaft that extends well out of the water itself.The float that turns the pump on and off usually looks suspiciously a lot like a toilet tank float, connected to a vertical rod.
Pedestal sump pumps are an older non-submersible type of pump used for removing water from buildings.
As rising water in the sump pit lifts the float, the float lifts the rod and the rod includes an adjustable screw-clamp fitting which pushes on the electrical contact of a mechanical switch to turn the pump on. As the water level drops the float falls and another screw-clamp fitting above the switch turns the pump motor back off.
Battery-backup sump pumps, use a rechargeable battery which is normally connected to live electrical power in order to remain fully charged. Shown here is a Sears battery-backup sump pump system which includes an marine-type automotive battery, battery charger, water sensor, an alarm.
Battery Backup Sump pump Pumping rate
Sears says the pump can remove 10,520 gallons on one charge. Do the math. 10,520 gals / 14.5 hours = 721 gallons per hour. 721/60 = 12 gpm. Sears rates the pump at 18 gpm. As long as water is entering your building at or slower than this rate this pump would be adequate.
Sears also says the pump can run for 14.5 hours on one charge. If power outages in your area are longer than this you'll need an auxiliary power source or multiple staged batteries.
If electrical power fails, the battery can still operate the sump pump - for a while. Before relying on a battery backup sump pump find out the typical duration of power outages in your area. If the duration of electrical power outages is likely to be longer than the battery life of your sump pump then you need either extra batteries or a generator.
Battery-backup sump pump systems are made and sold by:
We recommend this type of sump pump at homes where electrical power is frequently lost.
You're most likely to lose electrical power during a storm, which may be exactly when you most-need the sump pump, making battery backup sump pumps a good idea.
Water powered sump pumps, (as shown in the photos above or the sketch at left) use municipal water pressure and a venturi fitting to pick up and eject water from a building during flooding. Sketch shows the Aquanot pedestal pump - see PlumbingSupply.com listed below.
Usually water driven pumps are turned on manually by opening a water valve near the pump or by connecting a free-standing pump to a garden hose which in turn is connected to a hose bib. Water driven sump pumps work only where municipal water is provided . (In our opinion, running a water driven pump off of a home system may provide inadequate flow and risks overtaxing the well and pump system.)
Water powered sump pumps offer the advantage that the pump can operate when there is no electrical power.
Code legal? At least the older versions of these devices are illegal in many municipalities because their installation constitutes a cross-connection which can back-contaminate public water mains with unsanitary floodwaters. Before installing a water-powered sump pump check with your local building department to be sure it is permitted in your area. There may be newer versions that are code-approved: we invite more data and comment on this product.
See CROSS CONNECTIONS, PLUMBING for details.
Pump capability: the pumping capability of water driven pumps depends on the input water supply pressure and flow, the piping diameters, and the height that the water has to be lifted. Look closely at the flow rates claimed for the water driven sump pump you're considering and be sure it matches the pressure and diameter of the water supply piping to which you intend to connect it.
Most of the water powered pumps we reviewed gave no data on the volume of water that would be consumed from the municipal input source during a pumping operation. When a water powered sump pump says it can remove 900 gph, that number describes only the net additional water picked up by the pump, not the total water used from the municipal supply. If you're concerned about water consumption or water cost this approach may be need careful investigation.
The quantity of water used by a water powered sump pump depends on the water pipe diameter and the municipal water pressure that is being supplied. Typical water usage rates range from 7 gpm to 15 gpm.
Some water powered sump pump manufacturers such as Basepump™ do provide full product specifications on water removal capability as well as water consumption rate. For example, a high-powered water powered sump pump installed in a home supplied by municipal water at 40 psi and using 3/4" to 1" diameter piping with a ten-foot lift height can remove 1500 gallons of water per hour from the building and will consume an additional 900 gallons of municipal water.
Water & flooding alarm products are available in a variety of forms including battery-powered devices (we show one at Sewage Ejector Pump Grinder Pump) and even devices which can turn a light in a home or make a telephone call or inform an alarm company if a building is being subjected to flooding.
Considering the very high cost of flood damage cleanup and mold remediation, we consider flood alarms a great idea for buildings which are often left unattended.
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