A property manager in Chicago contacted us after tenants threatened to break leases over "the screaming elevator." The Otis Gen2 machine had a scratch so loud it could be heard two floors away in the stairwell.
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.
Mark the edge of the belt with a piece of white chalk. Run the car for 10 feet. otis gen2 scratch
Let’s look at real-world numbers.
| Action | Approximate Cost (US) | Typical Result | | :--- | :--- | :--- | | Do nothing (live with scratch) | $0 | Sheave failure in 18 months: $18,000 repair | | Clean belts & sheave | $500 - $1,000 | Silence for 4 months | | Replace 4 belts (labor + parts) | $3,000 - $6,000 | Silence for 2-3 years | | Recondition sheave + new belts | $12,000 - $18,000 | Silence for 8-12 years | In Gen2 controllers, a “scratch fault” or “scratch
The math is clear: investing in sheave reconditioning at the first sign of a persistent scratch is the most economical path.
Once you have identified the source, here are the mechanical fixes. Note: Always follow Otis Gen2 Installation Manual (Part No. 821281) for torque specs. A property manager in Chicago contacted us after
| Fault Code | Description | Typical Cause | |------------|-------------|----------------| | 1301 | Scratch memory checksum error | Battery backup failure, low voltage during reboot | | 1302 | Invalid scratch parameter range | Manual edit error, corrupted download | | 2103 | Door timing scratch mismatch | Door operator settings lost after power cycle | | 2400 | Drive tuning scratch lost | Encoder/belt replacement without re-learn |