Otis Gen2 Scratch -
Otis Elevator Company has not issued a global recall for the Gen2 scratch, but they have published several Field Service Bulletins (FSBs). Notably, FSB-EL-14-02 addressed belt slip detection and noise. The official position is that scratching is a "maintenance-sensitivity issue," meaning regular gauge-based tensioning and groove cleaning prevent the noise.
In 2018, Otis introduced an enhanced polyurethane formulation (Gen2 Premier belts) that significantly reduces the scratch phenomenon. If your building still has original "blue label" belts, you are in the high-risk category.
A scratch often occurs if the brake does not fully open.
If the belts are not perfectly perpendicular to the sheave grooves, the edge of the belt will rub against the side of the groove. This "edge-scratch" produces a consistent, metallic screech. This is often caused by improper installation of the drive motor or worn-out suspension bushings. otis gen2 scratch
Do not guess. Use this systematic approach to diagnose the Otis Gen2 scratch.
| Step | Action | What you listen for | | :--- | :--- | :--- | | 1 | Run the car empty at contract speed. | Scratch frequency: A scratch per belt rotation indicates a localized belt defect. | | 2 | Run the car with partial load (50% capacity). | Worse with load = belt slippage or sheave groove wear. | | 3 | Visually inspect belts stopped. | Look for "shine" (polyurethane dust) or visible steel cables. | | 4 | Check the sheave grooves. | Use a flashlight. Any pitting, rust, or glazing indicates a problem. | | 5 | Measure belt tension (Otis spec: 250-350Hz). | Uneven tension causes belts to "walk" sideways, creating a scratch. |
Critical note: If the scratch is accompanied by a rhythmic thump or vibration, stop the elevator immediately. That indicates broken steel tension members inside the belt—a safety risk. Otis Elevator Company has not issued a global
While less common, a slack governor rope can rub against the steel guide rails.
Otis Gen2 elevators are among the most popular machine-room-less (MRL) traction elevator systems in the world. Known for their flat steel belt technology and compact design, they offer reliability and energy efficiency. However, like any complex electromechanical system, they are prone to specific diagnostic codes.
Among technicians, one of the most dreaded and misunderstood fault codes is the "Otis Gen2 Scratch." If you have seen this notation on a service tool or heard a distinct metallic noise from the hoistway, you are likely dealing with a serious mechanical or electrical fault. If the belts are not perfectly perpendicular to
This article dives deep into what the "Scratch" reference means, the official fault codes associated with it, step-by-step diagnostics, and permanent repair solutions.
The Gen2 system uses small plastic or steel diverter pulleys to guide the belts. When these bearings fail, the pulley tilts.