- HVAC
- Air conditioner
H3
Gree H3 on an air conditioner: compressor overload protection
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
H3 protects the compressor from overload when its sensor detects too much temperature. In cooling or drying only the compressor halts, in heating the complete unit halts. Cut the power, clean the filter, clear the outdoor unit and call a technician.
Safety first
Stop and check this first
- Gree asks you not to repair the air conditioner yourself when H3 appears. If you notice a burning smell, a hot cord, abnormal noise or the breaker tripping often, switch it off, disconnect the power straight away and call an HVAC technician.
- The H3 overload protector is inside the outdoor unit: do not open it. Gree requires the technician to wait at least 20 minutes after cutting the power or to measure the capacitor below 20 V before touching the board.
Safe checks you can perform
- Read H3 on the dual 8 indicator
- Clean the filter and clear the unit after H3
- Gree's H3 diagram: protector, valve and refrigerant
Leave these tasks to a qualified professional
- Do not attempt this professional task: Check the overload protector and terminals
- Do not attempt this professional task: Leak test and charge if refrigerant is short
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Check the overload protector and terminals
What they doThe technician measures the OVC-COMP terminal and the overload protector and checks the board connection before blaming the compressor for H3.
They must show youthe OVC-COMP terminal resistance and the overload protector resistance against the manual's values.
In writingH3, the resistances measured, the terminal or protector corrected or replaced, and the date.
Leak test and charge if refrigerant is short
What they doIf the diagram reaches the refrigerant, the technician finds the leak with a detector, repairs it and charges according to Gree's service manual.
They must show youthe leak test with a detector, its result and the pressures in the mode where H3 appeared.
In writingH3, the leak point repaired, refrigerant recovered and charged (kg and type R410A), leak test result and date.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Read H3 on the dual 8 indicator
- Who:
- you.
- How:
- look at the code on the indoor unit display, where Gree shows errors on the dual 8 indicator. With H3, note whether it was cooling or drying (the indoor fan keeps running) or heating (the whole unit stops) and how long it had been running.
- Result that matters:
- having H3 confirmed with the mode and the hours of use before it.
- If the display reads H3:
- carry on with this page and also note how hot it was.
- If the display reads a code that is not H3:
- this page does not apply, look that one up.
- Evidence to keep:
- a photo of the display with H3, date, time, mode and running time.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO · Gree mini split air conditioner installation and owner's manual, Vireo Plus Ultra
Clean the filter and clear the unit after H3
- Who:
- you, power off.
- How:
- disconnect the power before cleaning, as Gree requires. Take out the filter, wash it in water below 45 °C or vacuum it, let it dry in the shade without a hair dryer and refit it. Check from outside that nothing blocks the outdoor unit's air inlet or outlet and remove it without opening the unit.
- Result that matters:
- lowering the compressor's working temperature, one of the points in the H3 diagram.
- If there was a lot of dirt or obstacles:
- note it, because Gree includes poor heat radiation among the causes of H3.
- If everything was clean:
- the remaining H3 checks are electrical or on the refrigerant, for the technician.
- Evidence to keep:
- photos of the filter and the outdoor unit surroundings before and after, with the date.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO · Gree mini split air conditioner installation and owner's manual, Vireo Plus Ultra
Gree's H3 diagram: protector, valve and refrigerant
- Who:
- certified technician.
- How:
- Gree says to start 30 minutes after powering the unit off. The protector connection and its resistance at ambient temperature are checked, then the electronic expansion valve terminal and coil, a possible refrigerant leak, the overload terminal connection to the board and heat radiation.
- Result that matters:
- finding which point in the diagram causes H3 before replacing the outdoor board.
- If the protector does not give the manual's resistance:
- Gree says to replace it.
- If everything above is fine and H3 persists:
- the diagram ends at the outdoor mainboard AP1.
- Evidence to keep:
- protector resistance measured, terminal condition, leak test result and the part replaced for H3.
Mains voltage, capacitors and pressurised R410A refrigerant: the H3 diagram is for the certified technician only.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- HVAC
- Brand
- Gree
- Product type
- Air conditioner
Known code variants
- Gree H3
- H 3
What it means
In Gree's service manual for the Sapphire SAP18 and SAP24HP230V1AH, H3 is the overload protection for the compressor. When the temperature at the overload sensor goes over its limit, the compressor stops and the outdoor fan follows 30 seconds later; the protection is released when the temperature drops. Gree checks the OVC-COMP terminal, the overload protector, the electronic expansion valve, the refrigerant and heat radiation. H3 on its own does not prove the compressor is faulty, and other Gree models may differ.
Warnings and stop conditions
- Highsource verified
Gree asks you not to repair the air conditioner yourself when H3 appears. If you notice a burning smell, a hot cord, abnormal noise or the breaker tripping often, switch it off, disconnect the power straight away and call an HVAC technician.
Evidence: Gree mini split air conditioner installation and owner's manual, Vireo Plus Ultra
- Higheditorial warning
The H3 overload protector is inside the outdoor unit: do not open it. Gree requires the technician to wait at least 20 minutes after cutting the power or to measure the capacitor below 20 V before touching the board.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
Symptoms and causes
Probable causes · in order
- Loose OVC-COMP terminalPossible
Gree's error list first names a loosened OVC-COMP terminal, which in normal state should measure less than 1 ohm.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
- Overload protector or its connectionPossible
The H3 procedure checks that the overload protector is well connected and measures its resistance at ambient temperature; if it fails, it is replaced.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
- Electronic expansion valvePossible
Gree checks the electronic expansion valve terminal and, if it is well connected, replaces its coil as the next step of the H3 diagram.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
- Refrigerant leak or shortagePossible
Among the H3 check points, Gree asks whether refrigerant has leaked and, if so, says to charge it according to the service manual.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
- Poor heat radiation or heavy loadPossible
A dirty heat exchanger, a poor radiating environment or a heavy load for a long time heat the compressor and appear in the H3 diagram.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
Virtual technician
Does H3 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Gree Comfort · 2022 · manual
- 2
Gree mini split air conditioner installation and owner's manual, Vireo Plus Ultra
Gree Comfort · 2019 · manual
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