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Defective thermostat.

Compressor Cycles (Other Than Normally Satisfying Thermostat) - Faulty thermostat.

Bryant · Comfort Alert Diagnostic Module

What does Defective thermostat. mean?

The thermostat is not functioning correctly, sending inaccurate signals or failing to maintain set temperatures, causing the compressor to cycle improperly.

Common Causes

  • Thermostat malfunction.
  • Incorrect programming or settings.
  • Low batteries (if applicable).

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the thermostat's display for error messages or unusual readings.

  2. 2

    Replace batteries if the thermostat uses them.

  3. 3

    Verify that the thermostat is set to the correct mode (Heat/Cool) and temperature.

  4. 4

    Contact a qualified technician to test or replace the thermostat.

Browse all codes in this manual (55)
Verified technical data. Last updated: April 2026

Related Faults

ALERT LED * flashes Yellow (misreported)Yellow ALERT LED * flashes (misreported) — Welded Contactor checkALERT LED 2 flashes YellowYellow ALERT LED 2 flashes — System pressure trip or compressor overloadALERT LED 3 flashes YellowYellow ALERT LED 3 flashes — Compressor short cycling
Source: Bryant Comfort Alert Diagnostic Module
Open Manual (Page 33)Search more codes in this manual