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T178

T178 - 4-20 mA Static Pressure Reset/VFD Fail

Carrier · Air Conditioning

What does T178 mean?

The 4-20 mA input for static pressure reset or VFD control has failed. These functions will be stopped.

Common Causes

  • Input signal failure
  • Wiring error

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Inspect the wiring related to the 4-20 mA input.

  2. 2

    Verify the functionality of the external device providing the signal.

  3. 3

    A technician should test the input signal and wiring integrity.

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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