The unit runs for a few minutes to a few tens of minutes, then the compressor and the outdoor fan stop, and it restarts later or shows an error. This is the unit protecting itself: the board cuts the compressor when current, temperature or pressure passes a limit, or when the board or a sensor itself reports wrongly. The table below lists the causes technicians found for exactly this symptom.
A summary of 266 public questions with this symptom that got a fix in technicians' groups (2021–2026). 250 name one main cause, 68 of them confirmed by the poster as the fix; in 16 the answer only lists possibilities, so they are not in the table.
Causes technicians found, by number of cases
Typical repair cases
Outdoor board (power stage, IPM, inverter)
- Daikin: Daikin 2 HP air conditioner shuts off after running for a few seconds. The control board has been replaced with another one but the problem persists, and no error code is displayed. – The compressor cut-out after a few seconds is most likely caused by overheating due to poor heat dissipation from the outdoor unit or the control board. Reinstall the cover and check the fan, clean the outdoor unit, then check the refrigerant, capacitor, sensors and oil level. (confirmed by the poster)
- Comfee air conditioner runs for 5 minutes then cuts out, showing error code Pc02, compressor hot, current rises to 4A after the board was replaced and the refrigerant was recharged and evacuated; the poster is asking for… – Error PC02 together with a hot compressor and 4A current under load indicates the control board or IGBT has failed, not a refrigerant problem. Recharging refrigerant or evacuating will not fix this fault. The correct approach is to check and replace with a compatible new board.
Temperature sensor
- Funiki: Funiki 1.5 HP air conditioner runs for about 15 minutes then cuts out, showing error code SC; the poster asks what the cause is. – Error code 5C is a fault in the indoor unit coil temperature sensor, not SC or FC. Check the sensor connection wiring and the sensor itself; if faulty, replace it with a new coil sensor and clip it at the correct position right at the pipe entry to the indoor unit.
- LG: LG 5HP Inverter ceiling-mounted air conditioner shows error code CH38, cuts out after running for about 30 minutes, with a pressure of 150 psi and a current of 20 A; the service company has repaired it several times… – The error indicates high pressure (150 psi) and a cut-out after about 30 minutes. Check the high-pressure switch located on the outdoor unit with a continuity meter. At the same time, clean the outdoor unit, check the fan and the refrigerant charge, and replace the pressure switch if it is faulty. (confirmed by the poster)
Faulty compressor
- Daikin: Daikin domestic air conditioner ramps the compressor up to 4.7 A, then cuts out (trips) the compressor after about 30 seconds, with no error code displayed; the control board and the electrical wiring have been checked… – The unit raises current to 4.7 A and then trips after about 30 seconds; suspect the compressor (block) is overloaded or the board/IPM is overheating. Run the unit without load after evacuating/recovering the refrigerant to check the compressor current and the board temperature, and measure the compressor winding…
- Panasonic: A Panasonic R32 air conditioner runs for about 5 minutes and then the outdoor compressor cuts out, and the board overheats and burns. The poster asks whether they should charge 32 kg of gas to fix it. – Do not charge R32 compressor refrigerant into a R410A gas system, because the pressure and current draw differ and the board will trip under load. Check the oil level, measure the resistance of the three windings against the old compressor, check the sensor, and replace with the correct R32 compressor and board if…
Power supply: low voltage, thin cable, breaker, lugs
- Daikin: The Daikin air conditioner does not start immediately when turned on; sometimes it is delayed 2-30 minutes, and sometimes it does not start at all. Power wiring, sensors, refrigerant pressure and the 226V supply have… – Measure the voltage at the moment the unit starts to check for voltage sag, and re-check the connections on the power supply wiring. Check whether other high-draw equipment on the same circuit runs at the same time. If the unit restarts after a power cut, wait about 2-3 minutes, as this is the normal protection delay…
- Panasonic: A Panasonic fixed-speed air conditioner keeps tripping the compressor when the voltage drops to around 180-190V. The poster asks whether this is the correct cause. – Low voltage (around 180-190V) increases the starting current and running current, which exceeds the overcurrent protection threshold, so the unit cuts out the compressor. The practical fix is to install a voltage stabilizer (for example Lioa) to keep the input voltage stable above 200V.
Low refrigerant, leak
- The air conditioner runs for a while and then the compressor trips out. Static pressure is 250, suspected clogged coil; the poster asks for the cause. – A static pressure of 250 is not enough to conclude anything. Measure the pressure while the unit is running, check for refrigerant leaks (soap bubbles or a leak detector), recover the refrigerant, evacuate and check system tightness, then charge the correct refrigerant quantity according to the unit's nameplate. If the…
- Daikin: Daikin air conditioner has stopped blowing air or runs unstably, displays error code UO, suspected fault on the control board or sensor. – The UO code on Daikin units is usually a refrigerant shortage: recover all the old gas, clean the coils, evacuate, then charge the exact weight in kg stated on the outdoor unit using an electronic scale. If the fault persists after charging the correct amount, further check the outdoor unit discharge/pipe temperature…
Signal wire, connector, terminal block
- Toshiba: Toshiba domestic air conditioner: the current rises to 7A, and after running for 15-20 minutes the outdoor unit cuts out. No error code appears on the unit itself, but the remote shows error 12. The control board and… – Error 12 on Toshiba units is usually caused by a signal communication fault between the indoor unit and the outdoor unit. Check and replace the signal wire, especially wire No. 3, and make sure all 3 wires are connected correctly and securely. If the fault persists, check the indoor unit board and the outdoor unit…
- Gree: The Gree 2HP inverter air conditioner runs for about 20 minutes, then the compressor cuts out and will not restart, displaying error E6, even though the wiring, the indoor unit sensor pair and both control boards have… – Gree error E6 is usually a communication fault between the outdoor unit and the indoor unit. Carefully check the signal wire and the crimped connectors, make sure the wire cross-section is adequate and the contact is good, and measure the power supply voltage. If the fault persists, check the outdoor unit mainboard and…
Overall
- In the real cases the outdoor board comes first, then sensors, the compressor, the refrigerant charge and the power supply – do not assume a low charge and add refrigerant.
- A weak supply (thin cable, loose lugs, low voltage at peak hours) is the cheapest cause to rule out: measure voltage and current at the moment the unit cuts out.
- A sensor (discharge pipe, outdoor coil, indoor coil) reading wrong or clamped in the wrong place makes the board see overheating – measure and compare with the exact model's table before replacing a board.
- Before condemning the compressor, check outdoor heat rejection, the outdoor fan and the charge – a new compressor in a dirty or blocked system fails again.
Note: this is technicians' field experience, not a manufacturer's document. Measured values and the order of checks can differ by model – check the exact model before repairing. If the unit shows an error code, start from that code's page.
Safety: switch off both the indoor and the outdoor unit before opening a cover or touching a board; the capacitors on the outdoor board stay charged for a while after power-off - wait for the board's lamps to go out and measure before touching. Refrigerant and high-voltage work belongs to a certified technician.