Home Forums General Discussion Technical Questions Disappearing Oil in National Wheel-O-Vator

I am an employee for a small, private college that has a vertical platform lift in a residence hall. The lift is a 2011 National Wheel-O-Vator (Division of ThyssenKrupp). I don't think either are in business any longer. In the four years that I have been employed I think it has been used twice. In Spring of 2024 it failed inspection due to inoperable. Schindler services our other elevators and agreed to take a look at it for a price. After many hours of troubleshooting it was determined to have a fuse blown w/circuit board that caused a disruption in the control board; door wiring was not correct, and the unit was out of oil. Fixed the first two issues, but could not find the leak. Passed 2025 inspection. Has not been operated since then. Lo and behold it fails Spring 2026 inspection - inoperable, no oil. Again, can't find the leak. Any ideas?

You might try calling your local TK Elevator branch.

So literally no hydro oil in the units reservoir, or are you or the inspector seeing a green or red LED indicating “low oil” fault? The unit won’t run if faulted and the inspector won’t reset it, he’ll just tell you it’s not working, or he might say, Its due to a “Low Oil” condition because the fault light indicates it. Might be something else triggering a “Low Oil” fault which simply means the platform did not reach its destination within a certain amount of time depending on how far upwards it travels. Typically a “platform lift” travels anywhere from 36” to maybe 60” but the rise varies. Point is if the lift cannot travel from bottom to top (or it’s next destination up) in a preset time, it trips on Low Oil or a Motor Protection so as to not overheat or burn up a constantly running motor. Or, if the unit utilizes two steel ropes and hydraulic piston, it may settle down too far from non use and trip a safety sensor.
So Montana gives the best advice. Call a reputable licensed elevator contractor.

ive seen 3 different times where people were dipping oil out of tank for their skid steer or tractor. but ive seen lots of times oil was leaking from the system. You need a standing full load pressure test overnight. if it passes you need a padlock on your tank.

Humans never cease to amaze me. lol I don't think this is the case since this building is in full view of our maintenance department (which I am a part of) but thank you for the reminder that anything is possible.

To elmcannic - Thank you for your reply.

Inspection was last month. Inspector mentioned it was inoperable before he left the premises. We were like that is impossible - we just had it fixed, it worked fine, and has not been used since it was fixed. Mtnc. went back to the building with the inspector and sure enough the oil had leaked out (that is why it wouldn't operate). But we can not find the leak.

It only travels 12" - one full step up.

12” rise (one full step). All areas underneath the lift are dry? Any Inaccessible area where the oil may have migrated out of view like a side wall next to the unit? Have you seen the floor area where the actual pump and reservoir are located?
For 12” of rise I’m surprised its hydraulic and not the screw drive type. The mystery continues and we’ve gotta hear the end of story.