What is a Small Submersible Pump?
Sump pumps are small submersible pumps installed in pits made low in the ground (a sump) to prevent flooding.
Sump pumps are ideal in domestic and low-flow settings, such as homes with basements that are prone to flooding or that lie below the water table.
Major Components of a sump pump:
- Motor: Powers the pump, driving the impeller.
- Impeller: Rotates to draw water into the pump before it is expelled through the discharge pipe.
- Float switch: Activates the pump when the water level in the sump rises to a predetermined level for automatic dewatering.
- Sump: A basin or pit where water collects via gravity, where the small sump pump is installed.
- Discharge pipe: Carries water from the sump pump to a secondary location, such as a storm drain or main sewer system.
- Check valve: Installed on the discharge pipe to prevent water from flowing back into the sump once the pump has stopped. This helps to maintain the pump's prime and prevents unnecessary on/off cycling.
- Housing/casing: This encloses the motor and impeller to protect them from water damage.
How do small submersible pumps work?
Automatic sump pump operating cycle:
- Water fills the sump pit, collected via gravity or pipes that feed into the sump.
- This water lifts a buoyant level control unit, usually a float switch, which activates the sump pump when it reaches a preset height.
- The sump pump transfers the nuisance water under pressure through the discharge pipework to a suitable location, usually the nearest foul water drain.
- The pump is deactivated when the float switch returns to its preset low level.
Common Uses of Sump Pumps
Small sump pumps are designed to remove nuisance and flood water from low-lying areas such as cellars and basements, this could be caused by:
- Excess rainwater
- Groundwater seepage
- Ice thaw
- Leaks from domestic appliances, like hoses and pipes
These pumps can effectively manage nuisance water in low-flow settings such as homes or small commercial settings. They are not suitable for pumping raw sewage or aggregates due to the presence of suspended solids, this requires a sewage pump.
Submersible sewage pumps may sometimes be used in a sump pump application, but never the other way around - for more information read Can Sewage Pumps be Used as Sump Pumps?
How to choose the best small submersible pump
The best small sump pump is one that reliably and effectively removes nuisance water without wasting energy.
This depends on the parameters of the application, such as flow rate and suspended solids content - consider the following factors:
Water volume - The sump must be big enough to handle the largest amount of water you may need to pump away, but small enough to avoid short cycling. This is when the water is slow to accumulate and start the pump but quick to fall to the level required to stop the pump - this frequent starting and stopping causes excessive wear and increased energy consumption.
The size of the pump, its components (such as the diameter of discharge pipework) and motor rating will affect the maximum flow rate it can achieve - this must be high enough to prevent a sump overflow should the maximum expected volume of water occur.
Sump positioning - The sump should be positioned at the lowest point in the ground for effective water collection, it should also be easily accessible for future maintenance needs.
Discharge point - Ensure water is discharged legally - all areas have different rules for where wastewater can be discarded, such as grassy fields, storm drains or the main sewer network. Check with your local water authority for more information.
Pipework - The type of pipework used to carry the nuisance water away will depend on whether the installation is designed for permanent or temporary drainage. Flexible hosing is suitable for short-term applications and lightweight for easy transportation, stronger materials such as steel or ABS plastic provide greater wear resistance for a permanent installation.
Solids handling - Small submersible pumps can be used for clean or dirty water drainage depending on the solids handling capacity of the impeller. This is determined by the impeller's free passage allowance and the strength of the pump's construction materials.
Can sump pumps run continuously?
Small sump pumps are designed to run for as long as necessary to bring water levels in the sump back to your predefined low level. Submersible pump motors are cooled by the liquid they pump, so running them continuously when the sump has been drained will cause overheating and premature wear.
T-T® Small Submersible Pumps
DR Steel - Domestic Drainage Pump
Stainless steel sump pumps with a multi-channel impeller for clear or grey wastewater, automatic as standard.
Corrosion-resistant stainless steel and fibre-reinforced plastic construction with a vortex impeller for up to 35mm solids handling.
Sumpy® - Fully Submersible Drainage Pump
A fully automatic sump pump with an integral float switch, technopolymer body and stainless steel shaft for a robust drainage solution.
T-T 100 - Clean Water Drainage Pump
Designed for clear water with non-abrasive particles up to 9mm, ideal for domestic and industrial settings.
Fibre-reinforced small submersible pump ideal for permanent installation, also suitable for pond drainage.
Ask the Experts
If you need help finding the perfect small submersible pump for your application, contact our experts by calling 01630 647200, emailing pumpsales@ttpumps.com or completing our online enquiry form.