Hydraulic elevators pump hydraulic fluid to a cylinder/plunger assembly that vertically moves the piston that raises the elevator cab and lowers it back down. The conventional cylinder/plunger assembly resides in a well hole directly beneath the elevator.
Years ago, these assemblies were installed with little or no protection from the subsurface elements. Without the ability to inspect the assembly beneath the surface, damage to the cylinder that would result in a hydraulic fluid leak could go unnoticed. The consequences could be soil and groundwater contamination. Fortunately, leaks have become less common as these elevators are replaced or modernized.
A maintenance contract does not cover the hydraulic leak repair. The cylinder/plunger assembly cost, including the required remediation of contaminants, can range from $30,000 to greater than $100,000. Prices vary due to the unknown condition of well holes and the drilling necessary to incorporate polyvinyl chloride (PVC) liner protection.
Hydraulic elevators must be housed in a controlled environment, requiring heating and possibly air conditioning. Remote piping running underground is another potential problem for temperature control and leakage.
Hydraulic elevators have a shorter life expectancy than traction elevators. They are subject to repair or improvements that do not apply to traction elevators. However, hydraulic elevators have a lower price point and are popular for lower-rise applications.