Two of the most common sump pump configurations are vertical cantilever and submersible pumps. There are tradeoffs to each configuration and knowing the equipment limitations can help you decide which pump is best suited for an application.
A true vertical cantilever pump has no bearings or seals operating in the process. The pump has a large base plate and robust bearing housing that extends a long shaft into the sump where the liquid end sits. Vertical cantilever pumps can be direct or belt drive.
Pros
- No submerged bearings or seals
- Higher process temperature
- Default continuous “run dry” capable
Cons
- Often more expensive
- More difficult install/removal
- Limited sump depth (around 11’/3.3m)
- Sensitive to duty point deviation (shaft deflection)
- Flooded sumps can ruin bearing housing/motor
- Requires lubrication schedule
A submersible pump is a close coupled electric motor and pump liquid end in which the entire assembly operates in the process fluid.
Pros
- Deeper sump installations
- Less sensitive to duty point deviation
- Often less expensive
- Easier install/removal
- No lubrication schedule
Cons
- Submerged bearings/seals
- Process temperature limits (194F/90C)
- Default 15 min in air rating (continuous in air available)
Recap
Each configuration has tradeoffs. The vertical cantilever pump eliminates exposed bearings and seals but offers less flexibility and often at a higher cost. It is better suited for shallow sumps, very high temperatures, and dialed in duty points to avoid shaft deflection. The submersible pump simplifies the solution with easier installation/removal, deeper sump installations, duty point flexibility, and often at a reduced cost compared to a similar vertical cantilever unit.
