Aircon repair / 5 min
Air conditioner not cooling? A gas leak case at the flare connection
A real-style repair guide for weak cooling caused by a refrigerant leak at the flared pipe connection.
Last updated: July 6, 2026 / Publisher: Tokai Home Everything
Short Answer
One possible reason an air conditioner does not cool is a refrigerant gas leak. In this case, the outdoor unit was running but the air stayed lukewarm, and inspection found leakage at the flared pipe connection. Simply adding gas can fail again if the leak remains, so the connection should be corrected before vacuuming and charging the proper refrigerant amount.
Checklist
- ・Weak cooling with the outdoor unit running can indicate a refrigerant leak
- ・Flare connections can leak due to installation condition or age
- ・Adding gas without fixing the leak can cause the same problem again
- ・Photos of the pipe connection, outdoor unit, and model label help the first check
The first sign was airflow without real cooling
In this case, lowering the remote-control temperature did not cool the room, and the indoor unit was blowing lukewarm air. Filter blockage can reduce airflow, but here the outdoor unit was running and the cooling itself was weak, so the refrigerant system needed to be checked.
The leak was at the flared pipe connection
The leak was found around the flared pipe connection on the outdoor-unit side. A flare connection can leak when tightening, surface condition, or age creates a small gap. It is not always visible from appearance alone, so proper inspection is needed.
Why adding gas alone is not enough
If refrigerant is added while the leak remains, the air conditioner may cool briefly and then return to the same symptom. The leaking point should be corrected first, then the piping condition and refrigerant amount should be handled properly.
Photos that help before asking
Useful photos include the indoor unit, outdoor unit, pipe connection, model label, and anything showing the installation age. If there is water leakage, abnormal noise, or an error display, a photo or short video also helps.
Avoid touching refrigerant piping yourself
You can check the filter and remote-control settings, but do not try to retighten refrigerant piping or flare connections yourself. Refrigerant, piping, and electrical parts are involved, so it is safer to share symptoms and photos first.
Need help with the actual work?
Photos and a short description help us understand what work may be needed.