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F1

F1 - Reverse phase detected in outdoor unit

MHI · R410A Systems

What does F1 mean?

This code indicates that the electrical phases supplying the outdoor unit are reversed. This is a critical power supply issue.

Common Causes

  • Incorrect wiring of the main power supply.
  • Incorrect phase sequence from the electrical panel.
  • Issue with the outdoor unit's power input.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Turn off the main power supply to the air conditioning system at the circuit breaker.

  2. 2

    Consult a qualified electrician to inspect and correct the phase wiring to the outdoor unit.

  3. 3

    Do not restore power until a professional has verified the wiring.

Browse all codes in this manual (58)
Verified technical data. Last updated: April 2026

Related Faults

E0E0 - Transmitting/receiving signal error in indoor unitE12E12 - Address setting conflict or auto address failureE14E14 - 3 flashes - Master/slave system wiring or SW settings error
Source: MHI R410A Systems
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