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T123

T123 - Circuit B High Saturated Suction Temperature

Carrier · Air Conditioning

What does T123 mean?

The saturated suction temperature in Circuit B is too high, potentially during startup. The circuit will stop.

Common Causes

  • TXV (Thermostatic Expansion Valve) problem
  • High system load

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Ensure the system is not overloaded with heat or cooling demand.

  2. 2

    Check for proper airflow across the evaporator coil.

  3. 3

    A technician needs to inspect the TXV and refrigerant charge.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

A051A051 - Compressor 1 Stuck On FailureA052A052 - Compressor 2 Stuck On FailureA055A055 - Compressor 1 Stuck On Failure (Circuit B)
Source: Carrier Air Conditioning
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