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T181

T181 — Loss of communication with Outside Air Unit

Carrier · Energy Recovery Ventilators

What does T181 mean?

Communication with the Outside Air Unit (OAU) has failed, prompting a reset of OAU data.

Common Causes

  • Wiring problem
  • OAU communication failure

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Inspect the wiring connecting to the OAU.

  2. 2

    Check for any error indicators on the OAU itself.

  3. 3

    Restart the OAU and the main unit.

  4. 4

    Reset the OAU data in the system settings.

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

Related Faults

1 Fault CodeFault Code 1 — OVERCURRENT10 Fault CodeFault Code 10 — PANEL LOSS11 Fault Code11 Fault Code — ID RUN FAIL
Source: Carrier Energy Recovery Ventilators
Open Manual (Page 47)Search more codes in this manual