Four-year-old LG losing gas: high-floor wind corroding the pipes
A four-year-old aircon should not be losing gas. But the outdoor pipe joints had already corroded. The unit sat on a high-floor ledge with no cover, taking direct wind and rain, so the connections aged far faster than a sheltered unit would.
By Team Snowflake | Reviewed 19 Mar 2026
Case summary
LG Wall-mounted4 years oldCondoPunggol, Singapore
- Concern
- The owner did not expect corrosion on a unit that was only four years old.
- Previous advice
- Homeowner assumed low gas was a servicing issue and requested a top-up
- Found
- Accelerated corrosion at outdoor unit connections due to high-floor wind and rain exposure
- Key check
- Visual inspection showed advanced corrosion on outdoor connections disproportionate to the unit's age. Consistent with unshielded high-floor exposure
- Result
- The leak was welded, the system recharged, and a weather shield fitted over the outdoor unit to cut direct rain exposure. Cooling has held steady since, and a follow-up inspection is scheduled to confirm the weld is holding.
What we were told
The aircon is not cooling well. It is only four years old, so I did not expect any major issues. My previous technician topped up the gas, but the cooling started dropping again soon after. The outdoor unit sits on my ledge.
What we checked
Gas loss on a unit this new points to either a factory fault or fast environmental wear. The top-up that faded again told us the gas was still escaping. The high-floor ledge placement was the first thing we wanted to check.
Gas pressure read below normal despite the recent top-up.
The outdoor unit sat on an open high-floor ledge with no overhead cover.
Pipe connections showed corrosion and oxidation well beyond what four years should cause.
A bubble test confirmed an active leak at the gas line connection on the outdoor unit.
The indoor unit pipe joints showed no signs of leakage, narrowing the fault to the outdoor side.
What we found
The outdoor unit took wind-driven rain head-on from the high-floor ledge. With no cover or barrier, moisture pooled around the pipe connections far more often than on a sheltered unit. That constant wetting sped up corrosion at the joints. At four years old, the damage already matched what we usually see on units aged six to eight in protected spots. The LG error code CH35 flagged low-pressure protection, which fit the refrigerant loss.
What fixed it
We welded the leaking connection and recharged the system. The corrosion was caught early and had not spread far, so a weld held up as a sound repair. We also recommended a weather shield over the outdoor unit to cut future moisture exposure. The owner agreed to both the repair and the shield. Given how exposed the unit is, we advised yearly checks on the connections and keeping an eye on the weld over the coming years.
Outcome
The leak was welded, the system recharged, and a weather shield fitted over the outdoor unit to cut direct rain exposure. Cooling has held steady since, and a follow-up inspection is scheduled to confirm the weld is holding.
What this case teaches us
A top-up that fades again is a leak, not low gas
- When cooling drops a few weeks after a top-up, the gas is escaping somewhere. The fix is finding the leak, not adding more refrigerant.
- An exposed high-floor unit corrodes faster. Wind and rain hit the pipe joints directly, so they can fail years earlier than a sheltered unit.
- A leak caught early can often be welded and shielded. Ask where the leak is and whether a cover would slow the corrosion.
Related reading
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