Code: H4🔧 Gree Mini Split

Gree Mini Split Error Code H4: Overload Protection, System Abnormal (Meaning, Causes, Fixes)

Reviewed 2026-10-24 · Based on 3 manufacturer & service sources

What the code means

Gree's 27 SEER Jasmine service manual lists H4 as "System is abnormal" and points to its overload and high-temperature analysis. Gree's after-sales error code manual lists H4 as "Overload protection" and explains it on its ducted and cassette (U-match) table: when the outdoor unit detects that the tube temperature is higher than the protective value, it reports overload protection and won't restart until the tube temperature falls back below that value and the compressor has been stopped for 3 minutes. If the protection happens more than 6 times, the unit stops recovering on its own and has to be switched off or have its power cycled. While H4 is active, the Jasmine manual says the compressor stops but the indoor fan keeps running in cooling and drying, and the whole unit stops in heating. H4 is a different code from H3, which is the compressor's own overload protector tripping.

Likely causes

Safe DIY checks

⚠ Before you start

Unplug the appliance or switch off its breaker before opening panels.

  1. Note when H4 appears: on a very hot afternoon in cooling, or in heating mode. Heat-related trips that clear when it cools off point to the operating conditions rather than a broken part.
  2. Clear leaves, grass, snow, covers or stored items from around the outdoor unit so air can flow freely in and out.
  3. Clean or wash the indoor filters, and make sure nothing blocks the indoor unit's air intake or outlet.
  4. If the outdoor coil is visibly dirty, switch the power off at the disconnect and rinse it gently with a garden hose. Don't use a pressure washer.
  5. Turn the unit off at the breaker for about 20 minutes, as Gree's chart does, then restore power and try again.
  6. If H4 comes back in normal weather, or the outdoor fan isn't spinning while the unit runs, call a licensed HVAC technician. The fan and board checks involve live electrical parts.

🛠 When to call a pro

  • Check the outdoor ambient temperature. Above 53 °C, Gree calls H4 a normal protection; run the unit once conditions improve.
  • With the unit disconnected from power for 20 minutes, check the heat-rejection environment of both the indoor and outdoor units and correct poor airflow or dirty heat exchangers.
  • Check whether the outdoor fan runs normally. If not, check that the fan terminal OFAN is connected well, then check the fan and its capacitor C1; Gree's chart has you measure between any two fan terminals with an ohmmeter, expecting less than 1,000 ohms, and replace the outdoor fan or capacitor as needed.
  • Look for a system blockage or an overloaded system (Jasmine's overload and high-temperature main detection points cover outdoor ambient, indoor and outdoor fan operation and the radiating environment).
  • If the temperature, airflow and fan all check out and H4 remains, Gree's chart ends with replacing the outdoor control board.

Parts that commonly fix it

Always match the part number to your exact model.

⚙

Outdoor fan motor (exact part for your outdoor model)

Gree replaces the outdoor fan when it doesn't run normally and its wiring is good; match the outdoor unit's model number.

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Coil cleaner (no-rinse or foaming)

For a dirty outdoor or indoor coil, one of the heat-rejection problems Gree checks for H4.

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Digital multimeter (CAT III rated)

For the fan terminal resistance check, done by a qualified technician with the power off.

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Sources

  1. Gree 27 SEER Jasmine mini split service manual: malfunction table (H4 System is abnormal, overload and high temperature; compressor stops with indoor fan running in cooling and drying, complete unit stops in heating) and high temperature and overload protection main detection points
  2. Gree Mini After-sales Service Manual (error code manual, Gree Australia): error code list (H4 Overload protection), U-match ducted and cassette table (tube temperature above protective value, 3-minute restart, lockout after more than 6 times) and 6.1 high temperature, overload, high power and abnormal system flowchart (53 °C, 20 minutes off, OFAN, capacitor C1, under 1,000 ohms, control board)
  3. Gree console service manual: system is abnormal (cool/dry all loads stop except indoor fan, heat all loads stop) and the high temperature prevention, high power, system abnormal flowchart

Last reviewed 2026-10-24. Always confirm against the manual for your exact model number.