Contents
What is a vertical immersible pump?
What's the difference between immersible & submersible?
How deep can a vertical immersible pump operate?
What liquids can vertical immersible pumps handle?
How are vertical immersible pumps installed?
What are some common maintenance issues?
Vertical immersible pumps are widely used in industrial and commercial applications where liquids must be transferred from pits, sumps, tanks or reservoirs. This guide explains how vertical immersible pumps work, where they are used, the liquids they can handle along with what maintenance considerations are most important for long-term reliability.
An immersible pump has the motor mounted above the tank with an extended shaft to the pump end at the bottom of the sump.
Submersible pumps are complete units, including the motor and the whole pump can be totally submerged whereas immersible pumps are mounted in a vertical position with the motor above the liquid and the pump end extended below the liquid level.
Submersible pumps are widely used for water & sewage handling applications, their compact dimensions and ease of use with integral float switches make them ideal for these situations. However, as the have standard carbon and ceramic mechanical seals and the materials of construction (generally cast iron or lower grade stainless steel) are limited, submersible pumps are unsuitable for use on liquids other than water, they are not designed for use with chemical or aggressive liquids.
On the other hand, immersible pumps can be designed and manufactured specifically for use in corrosive and aggressive situations and are made in a range of materials from 316 stainless steel up to engineered plastics such a polypropylene & PVDF. As the motor is above the pump it can be supplied in a specification to suit the environment including ATEZ zones 1 & 2. Column lengths can be supplied and even with shorter lengths (provided that the impeller is flooded at start up) the pump can still pump down to 6 meters.
The operating depth of a vertical immersible pump depends on its shaft length, bearing arrangement and construction materials.
Vertical immersible pumps are highly versatile and can handle a wide range of liquids, depending on the materials of construction and hydraulic design.
Most commonly handled liquids include:
Some models can handle limited solids or slurries (with appropriate design) although they are not typically intended for heavy solids like sewage solids or abrasive slurries.
Material selection is crucial. Pumps may be manufactured from cast iron, stainless steel, duplex steel, polypropylene, PVDF or other corrosion-resistant materials to ensure fluid compatibility.
If you are unsure we have a handy chemical compatibility table which helps take the guesswork out of material selection.
Vertical immersible pumps are usually installed in a fixed vertical position over a sump, pit or tank.
Some common installation methods include:
Proper alignment is essential to minimize vibration and shaft wear. The pump must be securely supported to handle axial and radial loads during operation.
Electrical connections, discharge piping and safety guards should be installed so that the motor remains protected from splashing or corrosive vapours. Ventilation around the motor is also important to prevent overheating.
Whilst vertical immersible pumps are generally reliable, regular inspection and maintenance are essential to maximise service life.
Common maintenance issues can include:
Most issues can be avoided through regular inspections, monitoring vibration, noise and temperature, maintaining correct liquid levels and correct material selection from the outset.
Because the motor remains above the liquid, vertical immersible pumps allow faster inspection and safer maintenance to fully submersible designs.
No, they rely on flooded suction and must have liquid covering the impeller before starting.
Many designs are seal-less or use vapour seals (limits the escape of vapours or liquid mist, not to seal pressurised liquid). This reduces leakage and maintenance compared to mech sealed pumps.
No, because the pump is already submerged, foot valves are not required.
Yes, when correctly sized and operated near their best efficiency point (BEP).
Not usually, but they must be securely mounted to prevent vibration and shaft misalignment.
Yes, shaft length, materials, bearings and discharge configurations are often tailored to the application.
Vertical immersible pumps are generally quiet, but increased noise may indicate cavitation, bearing wear or vibration issues.
Whether you’re emptying tanks, transferring chemicals or recirculating aggressive fluids, Crests vertical immersible pumps are engineered to fit your exact needs. They’re available in column lengths ranging from 300mm up to 6 meters, with options which require virtually no maintenance- thanks to designs without immersed bearings or seals.
Every sump is unique in size and contents, so we build each vertical pump to your precise specifications. Whether you need specific performance parameters, solids handling capability, or customized sizing, our team is ready to help design the perfect solution for you.