How to Reset a Mini-Split After a Power Outage

Updated 2026-08-29 · topics: Power & electronics · General reference

Do this first (works for nearly every brand)

• Stop the unit with the remote. Press the ON/OFF button so the indoor unit isn't trying to run while you cut power.
• Switch off the breaker that feeds the outdoor unit. Mini splits feed both indoor and outdoor units from this single breaker — that's why the breaker matters and the remote alone isn't enough.
• Wait a full 5 minutes. The inverter board holds charge in its capacitors; this wait is what actually clears the fault memory on most brands.
• Restore power and turn the unit on. Set a moderate temperature (24°C / 75°F) and watch the display for 10 minutes.

That's the whole procedure. On the majority of units this clears outage-related faults: memory-glitch codes, brief over/under-voltage trips, and stuck communication states.

Brand quirks worth knowing

• Midea / MRCOOL / Senville: these share Midea platform behavior. If the unit has a wired controller, hold the CHECK/ECO button sequence shown in your controller's manual to view stored codes after a reset — an outage often leaves the last fault in memory even though the unit runs.
• Gree / Tosot / Trane-legacy (Gree OEM): power-cycling clears the code display, but Gree boards keep the fault log. If the same code returns within a few days, treat it as an active fault, not an outage symptom.
• LG: after a clean power cycle, a CH error that returns instantly (within seconds of startup) usually indicates a hard fault — CH05/CH10-family communication codes after outages often trace to a grounded or damaged outdoor wiring run that the surge stressed.
• Daikin: the remote sensor check (hold CANCEL or the check button per model) shows stored codes as U4/E5-family history. Daikin units that ran during a brownout commonly log E5 (compressor overload) once and then run fine.
• Fujitsu / Mitsubishi-style rotary dials: no menu reset exists — the 5-minute breaker procedure is the reset.

What a reset will NOT fix

• Codes that return immediately on power-up (sensor open/short, board memory failures).
• Refrigerant-pressure codes (E5-family on many brands) — these trip because of a real pressure condition, and repeatedly resetting stresses the compressor.
• Burning smell, tripping breaker, or buzzing from the outdoor unit — these are stop-use conditions, not reset conditions.

The honest rule: a reset is a diagnostic, not a repair. One clean reset is informative; three resets in a row is how a small fault becomes a board replacement.

After the reset: watch for these codes

• Communication codes (E6/E7, CH05, EE, EC51-family): the outage may have stressed the inter-unit wiring or a surge damaged a board. Check the units both run before assuming the worst.
• Sensor codes (E1/E2-family): a brownout can corrupt a sensor reading; if the code clears and stays clear for a full day, ignore it.
• EEPROM/memory codes: these indicate board-level damage from the surge — the board usually needs replacement, which is a technician job.

Find your exact code in the brand list, and check the code's page for its verified meaning before buying parts.

Prevent it next time

• A surge protector sized for mini splits (surge-rated at the disconnect box) is cheap insurance — outage-related board damage is one of the most common non-warranty failures.
• If outages are frequent in your area, ask an electrician about a delayed-restart kit — many boards support a 3-minute random-start delay that protects the compressor from short-cycling when power returns.

Related guides

Mini-Split Communication Error: DIY Checks · Mini-Split Error Code Prefixes: What E, F, H, P Mean · Mini-Split Flashing Light Decoder: Blink Patterns · Mini-Split Repair or Replacement? A Practical Guide