Primary Submersible Sump Pump Works

Learn How Sump Pump Works

at Pumps Selection

Discover how primary submersible sump pump works so you know if your pump is working properly and you can make a better selection of best sump pump suited for your pumping needs.

  • There are many float types. How does each work? Is there a best?
  • There are many switch types.  How does each work? Is there a best?
  • Sump pits come in various sizes. Which is best for you?
  • Pumping performance is related to pump horse power. How many gallons per minute need to be pumped and which size of HP will do it?

We have applied sump pump works to application scenarios to help you hake the best selection for your pumping need.   See application scenarios below.

Float Basics

Sump pumps are activated when the water reaches a certain level in the tank/pit where it is located.  When the water reaches the height of the float the float switch is activated and the pump operates. See more details Sump-pump-float.

Switch Basics 

There are various types of switches: mechanical, electronic, magnetic.  The location of the swtich varies: inside the pump itself or external to the pump.

Piggy-back switches allow one to plug the pump motor cord directly into the AC outlet if the switch fails. See more details Sump-pump-switches. 

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Sump pits come in various sizes and shapes.

  • They generally range from 11" to 24" in diameter. 
  • Shapes vary.  Some have the same diameter at the top of the pit as at the bottom of the pit.  Others flare out at the bottom by an additional 6-8".

Other Features

  • Connection to electricity.  Sump pumps should not be operated with an extension cord.  Each pump in the pit should have its own electrical outlet and circuit breaker. 
  • Power cord length varies from 5' to 25'.  Length is important because it should be plugged directly into the outlet not into an extension cord.
  • Means for keeping the motor cool.  Old technology uses oil which can leak into the water.  New technology uses water.

  • Pump Housing.  The common materials used are thermoplastic, stainless steel and cast iron.

  • Frequency of usage:  Most are continuous duty construction.

  • Styles: Submersible pumps sit in the water and operate in the water.  Pedestal sump pumps sit above the water line.  The float is adjusted to determine when the pump will run. The motor is never in the water.

  • Usage of Electricity: The amps used vary by pump.  The variance is 3 to 12 amps.

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Pump Performance

Pumping performance is the rate at which water si pumped from the sump pit at a specific height.

Generally speaking, the greater the horse power (HP) the greater the pumping capability.

Pump efficiency defines how efficient the pump operates. The rate of efficiency varies from 10 to 80%.  Pump manufacturers generally do not indicate efficiency. As a consumer you can identify efficiency by HP and pumping capability.  A 1/2 HP pumping same volume of gallons per minute is more efficient that a 3/4 HP pump pumping the same volume of GPM the same height during the same time period.

Using the Basics to Understand Which Primary Sump Pump is Best for Your Situation.

  • Are you concerned about motor burn out during heavy rain storms causing the sump pump to run continuously for several hours?  The Watchdog Basement Sump Pump as well as the Little Giant, Flotec, Simer, Wayne and Zoeller Sump Pumps can run continuously without negative effect.   
  • Are you concerned about float switch failure while you are on vacation? The Watchdog Basement Sump Pump has dual switches.  If one fails the other one kicks in.  This is the best guarantee.  The Wayne Genius has no moving parts and will last 5 times longer than other switches, but eventually it too will fail.  The Little Giant has a diaphragm switch which is more reliable than a tether or vertical switch, but eventually has to be replaced.  Flotec and Simer, 1/2 and 3/4 HP, have a vertical float/switch.     
  • Are you concerned about removing the entire pump from the pit when the switch must be replaced? The Watchdog Basement Sump Pump switch is external to the pump cage. There is no need to remove the pump from the pit.  The switch is replaced by loosening the band holding the switch to the discharge PVC pipe, raising the switch out of the pit, replacing the switch, lowering it back down and tightening the band to the discharge PVC pipe. StormPro also has an external switch mechanism; however it is not dual. 
  • Can your current pump handle the volume of water from heavy rain storms? If your sump pit is 18" in diameter, think about placing two 6" diameter Watchdog Basement Sump Pumps in the base of the pit.  Placing two dual switch Basement Watchdog Primary Sump Pumps in the pit would give you added peace of mind.  You would have four operational switches. Or you may be able to place two primary pumps one on top of the other and still have room for a battery backup pump on the sump pit floor. 
  • Are you concerned about electricity consumption? The Watchdog Basement Sump Pump is rated most energy efficient.  The Little Giant Pump is rated second.  
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