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Saniflo 21 Residential Water Pump, Grey,1/3 HP Reviews

4.6 Rating 125 Reviews
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The Saniflo MPN 21 residential water pump transforms basement remodeling projects by eliminating traditional drainage limitations through its specialized 1/3 HP motor configuration. This grey-colored thermoplastic housing unit measures exactly 8.75 inches in height, 9 inches in width, and 10.25 inches in depth, positioning itself as the compact solution for residential drainage challenges where gravity flow proves impossible.  Weighing 13 pounds, this Saniflo pump delivers 18 gallons per minute discharge capacity at its maximum 14-foot vertical lift specification, making it the definitive choice for basement apartments, laundry installations, and remote kitchen additions where conventional drain systems cannot reach the main sewer line. Unlike standard sump pump configurations designed for groundwater removal, the MPN 21 features three strategically positioned 1.5-inch inlets—two low-profile side inlets with integrated check valve protection and one top-mounted inlet—enabling simultaneous wastewater collection from multiple fixtures without requiring complex manifold assemblies.  The unit's 120-volt, 60-hertz electrical specification draws a maximum 4.5 amperes during operation, qualifying it for standard residential circuit integration while maintaining CSA certification under both IPC and NSPC plumbing code standards. Precision-Engineered Oil-Filled Motor Technology Delivering Maintenance-Free Performance The permanently sealed oil-bath motor assembly within the Saniflo 021 eliminates traditional maintenance intervals found in conventional drain pump applications. This 0.3 horsepower induction motor operates at precisely 3,600 revolutions per minute, driving a direct-coupled impeller through a single spindle shaft that minimizes mechanical complexity and potential failure points.  The oil-filled enclosure surrounding the motor provides continuous lubrication, thermal protection through efficient heat dissipation, and acoustic dampening that reduces operational noise to just 44 decibels measured at three feet—quieter than most residential dishwasher cycles and significantly below the threshold requiring hearing protection in occupied spaces. The thermoplastic housing material surrounding the motor assembly resists corrosion from prolonged wastewater exposure while maintaining structural integrity at operating temperatures up to 140 degrees Fahrenheit.  This temperature threshold accommodates hot water discharge from washing machines, dishwashers, and utility sinks without requiring cooling periods or thermal protection devices. The polyethylene construction also provides chemical resistance against common household cleaning agents, laundry detergents, and kitchen effluent containing mild acids or alkaline compounds. Engineering specifications reveal the motor's 30-microfarad capacitor rating ensures consistent starting torque under varied load conditions, preventing the motor stall issues that plague less sophisticated residential pump designs.  The pressure switch activation mechanism responds to water level changes within the 2.75-gallon capacity chamber, triggering motor engagement only when sufficient volume accumulates for efficient discharge cycles lasting between two and ten seconds depending on horizontal pipe run configurations and vertical lift requirements. Three-Inlet Configuration Maximizing Installation Versatility Across Residential Applications The Saniflo MPN 21's triple inlet design accommodates diverse fixture combinations without requiring additional collection pits or intermediate pumping stations. Both side-mounted 1.5-inch inlets incorporate factory-installed check valves that prevent backflow during system operation, eliminating the need for separate valve installation and reducing potential leak points in the drainage assembly.  These low-profile inlets position just above the unit's base, facilitating gravity drainage from floor-level shower bases constructed on minimum 6-inch elevated platforms using dimensional lumber framing techniques. The quarter-inch per foot slope requirement toward the pump ensures consistent flow without standing water accumulation in horizontal drainage runs. The top-mounted inlet provides alternative connection routing for fixtures positioned above the pump housing,

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“Replaced a huge tank with sump pump for this. The sump had super high flow, so it constantly overloaded the drain (probably poorly installed). This pump is adequate for a utility sink and washer. Much quieter, and my drain no longer rushes or gurgles. Also, the old tank was impossible to seal, so it let out nasty water smells. This unit fixed all my woes. Better yet it fits under my utility sink gaining me an extra 10 sq. Ft. In the garage. I don't understand why these aren't the golden standard.”
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Posted 8 years ago
“Works great I installed it in the basement to pump up the washer water keeps up and was fairly easy to install.”
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Posted 8 years ago
Christianna B
Verified Reviewer
“Works Great! My installation is 15 ft. vertical lift and 30 ft. horizontal to the sewer drain.Discharge line can only run 18" horizontal prior to vertical lift. Luckily, that was not an issue with my install location.”
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Posted 8 years ago
“Good so far.”
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Posted 8 years ago
“was pretty easy to install, works great. I did install a heavier duty one way valve in the discharge line, because the one that came with it is of low quality and wouldn't seal.”
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Posted 8 years ago
“Great product installed myself no need to break concrete floor”
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Posted 8 years ago
“For me, I use this under a sink in my wet bar, I do not have floor drain lines, as, mine are located 3 feet off the floor. My Saniflo pumps the “waste Water” from the sink through 40’ of 3/4” PVC pipe.It works excellent. This is my third unit in the past 6 years.What I have learned from past experiences and why I’ve been through 3 of them, is, this pump is NOT a grinder pump, don’t expect it to chew up food, it’s not a garbage disposal.2nd, since it does not just flow downward to a gravity drain like the rest of your home, it actually needs to PUMP the fluid, so don’t keep pouring sugary type drinks into it(like soda) or other, even beer and alcohol WITHOUT running water with it.If you do, the sugar base will foul the internal float and prevent it from turning on and the fluids will back up in your sink.YOU MUST RUN WATER WHEN POURING ANYTHING IN THE DRAIN OTHER THAN WATER ITSELF.Trust me, I’ve replaced 2 of these already.If you watch what goes into it, your good to go.I do now.I have no issues with cold water.I have no issues with hot water.I have no issues with the “Pumping” noise it makes.The Saniflo works great.Buy it, you won’t be disappointed.”
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Posted 8 years ago
“Love it.. I added this to my bar sink in the basement. Piping was easy, setup was easy. I would recommend this to anyone who want to add a sink in the basement without going through expense of underground piping. I installed the 1" discharge piping using 1" PET, which is flexible. Just make sure you have the proper drain slope and follow the manufacturers installation instructions. Also, you should purchase the alarm sensor for $50.”
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Posted 8 years ago