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402

LOOP CONTACTOR FAULT

Otis · DSD 412 Elevator System

What does 402 mean?

The DSD 412 drive detects that the Loop Contactor auxiliary contact failed to pick up or drop out within the expected timeframe. This behavior is governed by the setting of parameter #102.

Common Causes

  • Defective Loop Contactor Auxiliary contact, failing to provide proper feedback.
  • Defective main Contactor, potentially due to an open coil or mechanical binding.
  • Defective Pilot Relay LPR.
  • Electrical interference originating from other elevator relay contact circuits.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check for proper feedback from the Loop Contactor Auxiliary contact at terminal TB1-7.

  2. 2

    Inspect the main Contactor for an open coil or any signs of mechanical binding.

  3. 3

    Check the Pilot Relay LPR for proper operation.

  4. 4

    Investigate and mitigate any interference from other elevator relay contact circuits.

Browse all codes in this manual (57)
Verified technical data. Last updated: April 2026

Related Faults

117/118SERIAL COMMUNICATION FAULT400MOTOR OVERLOAD FAULT401EXCESSIVE FIELD CURRENT
Source: Otis DSD 412 Elevator System
Open Manual (Page 85)Search more codes in this manual