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EA, Eb

Outdoor Board LED green (twice) and red (once) blink alternately after startup - Incorrect wiring between indoor and outdoor unit (Polarity is wrong for S1, S2, S3)

MHI · Air Conditioning

What does EA, Eb mean?

After the initial 'startup' sequence, if the outdoor unit's LED1 (green) blinks twice and LED2 (red) blinks once alternately, it indicates incorrect wiring between the indoor and outdoor units, specifically wrong polarity for S1, S2, S3.

Common Causes

  • Incorrect wiring between the indoor and outdoor unit (Polarity is wrong for S1, S2, S3).

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Turn off the main power supply to the unit.

  2. 2

    Verify the wiring between the indoor and outdoor units, paying close attention to the polarity of S1, S2, and S3.

  3. 3

    Correct any miswiring and then restore power.

Browse all codes in this manual (124)
Verified technical data. Last updated: April 2026

Related Faults

00Outdoor Board LED only green lights up after startup - No outdoor unit of address 0 / Remote controller transmission wire open1OPERATION INDICATOR lamp blinks 1 time (Pattern A) - Indoor/outdoor unit communication error (Transmitting error - Outdoor unit)14OPERATION INDICATOR lamp blinks 14 times (Pattern A) - Other errors
Source: MHI Air Conditioning
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