In this troubleshooting case, a customer reported an unusual issue while installing a home lift equipped with two manually operated cabin folding doors. Whenever one folding door was closed first and the second door was then closed, the previously closed door would unexpectedly reopen.
Problem Description
During the installation of a custom home lift project, our customer encountered an unusual issue with the cabin doors.
The lift cabin was designed with two manually operated folding doors arranged in a center-opening configuration. The user closes one folding door first and then closes the second folding door.
However, an unexpected problem appeared:
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Close Door A → Door A stays closed.
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Close Door B → Door A suddenly opens again.
This made it impossible to completely close both doors in a normal sequence.
Although the lift itself operated correctly, the cabin doors could not remain closed simultaneously. Review the video here.
Initial Investigation
At first, several possible causes were considered:
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Incorrect door alignment
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Uneven floor installation
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Door frame deformation during transportation
After checking all mechanical components, no faults were found.
Both folding doors moved smoothly and were correctly installed.
Root Cause Analysis
The actual cause turned out to be air pressure inside the cabin.
Because the cabin was very well sealed, closing the second folding door compressed the air inside the cabin.
When the final door reached its fully closed position, the trapped air had nowhere to escape.
The resulting air pressure pushed against the first closed folding door, causing it to reopen slightly.
This effect is similar to closing a tightly sealed room door or a refrigerator door where air pressure temporarily pushes another door open.
Why Not Simply Lock the First Door?
One possible solution would be to lock the first folding door after it is closed.
However, this creates another problem.
Since the lift stops at multiple floors, passengers must be able to open either folding door from different landing positions.
If one door is mechanically locked, it may become inaccessible at other floors, reducing usability and potentially creating inconvenience for users.
Therefore, locking the first door is not an ideal solution.
Design Improvement
After analyzing the issue, we concluded that the cabin design itself needed a small modification.
The recommended improvement is:
Leave approximately 5 mm clearance between the bottom of each folding door and the cabin floor.
This small gap allows air to circulate freely when the second door is closed.
Benefits include:
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Eliminates trapped air pressure.
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Prevents the first door from reopening.
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Maintains smooth door operation.
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Improves overall user experience.
Lessons Learned
This issue was not caused by installation errors or component failure.
Instead, it was a minor design oversight resulting from excellent cabin sealing.
In home lift projects, details such as ventilation, pressure equalization, and door clearance can sometimes affect the user experience more than major mechanical components.
Even a small 5 mm gap can completely solve the problem.
Conclusion
Every project provides valuable experience.
This troubleshooting case reminded us that good engineering is often found in small details.
By allowing proper airflow inside the cabin, the folding doors can operate smoothly without additional hardware or complicated mechanisms.
Sometimes, the simplest solution is the most effective one.
If you are planning a home lift installation, browse our full range of home lifts to find the right model for your project.
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