- HVAC
- Air conditioner
PU
Gree PU on air conditioner: outdoor capacitor charging fault
Risk level
High
Professional inspection is recommended.
Urgency
High
Quick answer
PU on a Gree indoor Dual-8 display signals a capacitor charging malfunction on the outdoor unit control board. In cooling or drying the compressor stops while the indoor fan keeps running; in heating the entire unit stops. Switch off the power and book a technician.
Safety first
Stop and check this first
- Gree's service manual requires shutting down power and waiting 20 minutes, or measuring with a DC voltmeter until the electrolytic capacitor is below 20 V, before touching reactor L or board AP1.
- Always turn off the air conditioner and disconnect the power before cleaning or inspecting, and never remove the unit panels yourself, as warned in the Gree owner's manual.
Safe checks you can perform
- Confirm code PU on the Dual-8 display and check unit behavior
- Turn off the air conditioner and disconnect power without opening panels
- Measure AC voltage at XT (L and N) and capacitor voltage after 1 minute
- Discharge capacitor below 20 V DC and inspect reactor (L) wiring
Leave these tasks to a qualified professional
- Do not attempt this professional task: Measure AC supply voltage across terminals L and N on the XT wiring board
- Do not attempt this professional task: Check capacitor voltage (> 200 V) and inspect reactor (L) after discharging (< 20 V DC)
- Do not attempt this professional task: Replace outdoor mainboard AP1 if the charging malfunction persists
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.
Measure AC supply voltage across terminals L and N on the XT wiring board
What they doThe technician measures the alternating voltage across terminals L and N of the outdoor XT wiring board to confirm it is between 210 VAC and 240 VAC (and within the 180 VAC to 260 VAC troubleshooting range).
They must show youthe AC voltmeter reading across terminals L and N on the XT board.
In writingcode PU, the AC voltage measured at terminals L and N, and any supply repair needed.
Check capacitor voltage (> 200 V) and inspect reactor (L) after discharging (< 20 V DC)
What they doWith normal AC input, the technician turns on the unit for 1 minute to check if voltage across the electrolytic capacitor exceeds 200 V; if not, the technician shuts down power for 20 minutes (or verifies < 20 V DC across the capacitor) and checks and reconnects the reactor (L) wires.
They must show youthe capacitor voltage reading and the connection state of reactor (L).
In writingthe 1-minute capacitor voltage, confirmation of discharge below 20 V DC, and any reconnection performed on reactor L.
Replace outdoor mainboard AP1 if the charging malfunction persists
What they doIf supply voltage is within 180 VAC to 260 VAC and reactor (L) wiring is normal (or capacitor voltage exceeds 200 V after 1 minute while PU remains), the technician safely discharges the capacitor below 20 V DC and replaces outdoor control board AP1.
They must show youthe completed supply and reactor L checks together with the replaced outdoor mainboard AP1.
In writingthe part number of replacement outdoor board AP1, the voltage readings recorded before replacement, and the 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.
Confirm code PU on the Dual-8 display and check unit behavior
- Who:
- you.
- How:
- verify that the indoor Dual-8 display reads PU and note whether the indoor fan keeps running without cooling in Cool/Dry mode, or whether the complete unit stops in Heating mode.
- Result that matters:
- confirming that the unit is in Gree's capacitor charging protection state (PU).
- If PU is displayed with that exact behavior:
- check whether your home supply experienced a dip or outage.
- If a different two-character code is shown (such as PH, PL, or P8):
- follow the procedure for that code.
- Evidence to keep:
- a clear photo of PU on the indoor Dual-8 display and the active operating mode.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
Turn off the air conditioner and disconnect power without opening panels
- Who:
- you.
- How:
- turn off the air conditioner and disconnect the power supply at the breaker as warned in the Gree owner's manual to avoid electric shock, and do not remove any unit panel.
- Result that matters:
- making the system safe and allowing the outdoor capacitor to discharge.
- If there was a temporary power fluctuation:
- wait 20 minutes with power off, restore power once, and see if PU clears.
- If mains power was steady or PU returns right after restarting:
- switch the breaker off and call an HVAC technician.
- Evidence to keep:
- whether any household voltage dip occurred and whether PU returned after a 20-minute power-off wait.
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
Measure AC voltage at XT (L and N) and capacitor voltage after 1 minute
- Who:
- technician for PU.
- How:
- use an AC voltmeter to check whether voltage across terminals L and N of the XT wiring board is within 180 VAC to 260 VAC (210-240 VAC), then turn on the unit, wait 1 minute, and measure whether voltage across the two ends of the electrolytic capacitor exceeds 200 V.
- Result that matters:
- separating an external power supply fault from an internal capacitor charging failure.
- If input voltage is outside 180-260 VAC:
- repair the power supply to restore 180-260 VAC and restart.
- If input voltage is within 180-260 VAC:
- if capacitor voltage exceeds 200 V, replace outdoor mainboard AP1; if below 200 V, discharge and inspect reactor L.
- Evidence to keep:
- measured AC voltage across L and N at XT and measured capacitor voltage 1 minute after power-on.
The electrolytic capacitor on outdoor board AP1 retains hazardous voltage: shut down power and wait 20 minutes or measure with a DC voltmeter until below 20 V before touching wiring.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
Discharge capacitor below 20 V DC and inspect reactor (L) wiring
- Who:
- Gree service technician.
- How:
- shut down power and wait 20 minutes (or measure across the two ends of the electrolytic capacitor with a DC voltmeter until voltage is below 20 V), then check whether reactor (L) and its connection wires are loosened, pulled out, or damaged.
- Result that matters:
- verifying the reactor (L) circuit before condemning outdoor mainboard AP1.
- If a reactor (L) wire is loose or pulled out:
- reconnect the wire of reactor L properly, power on, and verify that PU is eliminated.
- If reactor (L) wiring is normal and PU is not eliminated:
- replace outdoor mainboard AP1.
- Evidence to keep:
- DC voltmeter confirmation below 20 V prior to inspection, condition of reactor L leads, and restart test result.
Never touch reactor L or board AP1 terminals until DC voltage across the electrolytic capacitor has been verified below 20 V or power has been off for 20 minutes.
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
- error PU Gree
- fallo PU aire Gree
- Gree AC PU code
- Gree error PU
- Gree PU
- P U
- PU
What it means
According to the Gree Sapphire service manual (models SAP18HP230V1AH/AO and SAP24HP230V1AH/AO), code PU on the indoor Dual-8 display indicates a charging malfunction of the capacitor (`Capacity charging malfunction`) in the outdoor unit. During cooling and drying operation, the compressor stops while the indoor fan continues operating; during heating operation, the complete unit stops. Seeing PU on the display never proves by itself that the outdoor control board AP1 has failed.
Warnings and stop conditions
- Highsource verified
Gree's service manual requires shutting down power and waiting 20 minutes, or measuring with a DC voltmeter until the electrolytic capacitor is below 20 V, before touching reactor L or board AP1.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
- Mediumsource verified
Always turn off the air conditioner and disconnect the power before cleaning or inspecting, and never remove the unit panels yourself, as warned in the Gree owner's manual.
Evidence: Gree mini split air conditioner installation and owner's manual, Vireo Plus Ultra
Symptoms and causes
Probable causes · in order
- Abnormal AC supply voltage at outdoor terminal board XTCommon
The AC input voltage across terminals L and N on the outdoor XT wiring board falls outside the required 180 VAC to 260 VAC operating range (210-240 VAC nominal).
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
- Loosened or pulled-out reactor (L) connection wireCommon
A connection wire on the outdoor reactor (inductor L) has loosened or pulled out, interrupting the capacitor charging path.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
- Damaged reactor (L) in the outdoor unitPossible
The reactor (L) connected to the outdoor charging circuit is electrically damaged or open.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
- Malfunction of the outdoor control board AP1Possible
With normal AC supply voltage and intact reactor (L) wiring, the charging circuit or sensing stage on outdoor mainboard AP1 fails.
Evidence: Gree Sapphire installation, service and troubleshooting manual, SAP18HP230V1AH/AO and SAP24HP230V1AH/AO
Virtual technician
Does PU 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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