Drainage pumps: When the right pump makes all the difference
Pumps are integral to many plumbing systems — sump pumps, sewage ejector pumps, pumps for radiant heating, pumps for water heaters and boilers. Natural disasters of immense size and power put pumps for emergency water removal front of mind.
The wind and water assault on the Houston metro area by Hurricane Harvey in late August and the water surge power of Hurricane Irma in early September got us thinking about how pumps of all shapes, sizes and capacities are a vital tool in the recovery process. Extensive damage can be prevented or ameliorated if floodwater is pumped out quickly. The sooner water is pumped out, the sooner things can begin to be dried out, and damaged contents and structure removed.
In areas without basements, we’re told that water typically flows out as the floodwaters begin to recede. In some situations, as in many of the affected Texas homes, once the water recedes so the house can be safely entered, the residual can be pumped out. The furniture and fixture removal can happen quickly and efficiently, and any excess water can be swept or pumped out before remediation, which includes ripping out the flooring and removing sheetrock a set level above the flood water line.
What kinds of pumps come into play depend on geography and home construction. In areas where there’s no basement, professionals often turn to utility or water transfer pumps. Water transfer pumps come in a range of sizes from lightweight pumps designed for use around a home to larger pumps for site flooding. The speed of water transfer depends on the size of the suction and discharge ports, which typically range from 1 to 4 inches.
A utility pump is a small, portable device that automatically drains an area of unwanted water. Commonly, it is not permanently installed and is plumbed so that its discharge is directed away from the drained area. In an emergency, a utility pump is the first pump you want to have on hand to move water quickly and efficiently from place to place.
In areas where there are basements and other below-ground spaces, the humble sump pump is as valuable a tool as they come. California contractors had the experience of replacing quite a few sump pumps after last winter’s record rains fell long enough to alleviate the years-long drought. Pumps that had not been used — or needed — for several years either aged out or burned out and had to be repaired or replaced.
To “de-water” a space flooded by a natural disaster, seasonal rainfall or ruptured pipes, the location of the collected water matters. Even in areas like Houston where basements aren’t typical, there are underground structures such as parking garages where a sump pump could be utilized. For most residences, where water collects on a ground floor, water transfer pumps and utility pumps are the right tool. Once most of the water is pumped out, and contents removed, then large fans and industrial strength dehumidifiers can be deployed.
Sizing and installing
When is a sump pump the right equipment for water removal? The sump pump is a device that simply suctions undesired water or other liquids out of a basement or other pit and moves it up, out and away from a building’s foundation to a suitable location. Typically, if the home or structure is located in a low-lying area, the ground is not graded away from the building, or there is evidence of dampness in basement walls, a pump should be installed. In new construction a pump may be required by local codes or be specified into construction plans. Sump pumps are used primarily for non-potable water applications containing solids no larger than a half inch.
These pumps come in submersible and pedestal versions usually contained in a basin designed to pump excess water that enters unwanted areas. In general, “submersible” means the motor resides under a pre-determined level of water in the basin with both pump and motor inside a sealed housing. “Pedestal” means the motor resides above an acceptable water level. Here are some of the sump pump sizing and installation tips offered by top manufacturers.
- Properly size the pump for the application, which factors in the vertical lift of the discharge line and the distance the line runs before discharging. Match the width of the discharge line with the width of discharge on the pump. If pumps are over-sized, the new generation of circulators and pumps helps substantially to offset the damage that can be done when this occurs.
- Install a vent hole in the discharge pipe below the check valve.
- Always follow manufacturer’s recommendation for discharge size, and don’t go below that size.
- Install a check valve in the discharge line to prevent backflow. If not installed, the liquid draining back can cause the pump to cycle too often, and drain back can cause the pump impeller to turn backwards and unscrew itself from the motor shaft.
- The switch should not be installed directly underneath the inflow of water. This can cause it to stay in the off position. Keep the switch away from the sides of the pit to prevent hang-up.
- Use the same size PVC pipe as the pump’s threaded discharge, usually 1 ½ inches.
- Avoid setting a ground water pump directly on a gravel base instead of the appropriate manufactured stand. This step can prevent pebbles getting into the pump and locking up the impeller.
- • Clean out the sump pit before installing the sump pump. If you don’t, collected debris can potentially jam the pump’s impeller.