New LG unit shows CH38 in Hougang: undercharged from install, not a leak
CH38 is LG's low-refrigerant code, and on an older unit it often points to a leak. This LG unit was newly installed in a Hougang flat and had never cooled quite right. The concern was a hidden leak or a warranty-level fault, not a step missed during setup.
By Team Snowflake | Reviewed 11 Jul 2026
Case summary
LG Wall-mounted1 years oldHDBHougang, Singapore
- Concern
- The fear was a costly warranty claim or an active leak needing to be traced and sealed before cooling was reliable again.
- Found
- The installer had completed the vacuum step at install but never topped the refrigerant charge up to the correct level afterward, leaving the system undercharged from day one with no active leak anywhere in the line
- Key check
- A pressure check plus a bubble test and electronic leak sweep across the accessible line and outdoor connections turned up no leak, which pointed to a charge that was never completed at install rather than gas escaping
- Result
- Cooling came back to where it should have been from the start, and the CH38 code has not returned since. No parts were replaced, and no leak was ever found.
What we were told
The unit had gone in only weeks earlier, and cooling was never quite right from day one. The living room stayed a touch warmer than expected, and CH38 began flashing on the display. A quick search on CH38 pointed to low refrigerant, which read as a leak in a system still under warranty.
What we checked
CH38 alone does not confirm a leak. It is the LG code for low refrigerant pressure. That pressure can drop because gas is escaping, or because the system was never charged to the right level in the first place. On a unit only weeks old, the second explanation deserved a proper look before assuming a leak needed tracing.
A pressure check showed the system running low. There was no pattern of gas fading away over time, the kind an active leak usually leaves.
A bubble test and an electronic leak detector were run across both outdoor connections and the full accessible line. Neither picked up a leak.
Installation notes showed the line had been pulled to a vacuum before charging. The gas amount was never checked against this pipe run afterward.
What we found
The line had been vacuumed at install, but the charge was never topped up to match the actual pipe run afterward. The system ran on less refrigerant than it needed from the very first day, not because any of it had escaped. That shortfall was enough to drop the reading below the point where CH38 triggers. It was also enough to keep cooling a step short of where it should have been.
What fixed it
No leak meant no sealing work and no parts to replace. The system was pumped back down to a full vacuum to clear out the trapped air alongside the low charge. It was then filled to the level this LG model needs for its pipe run. The unit was run and checked again before closing up. The fill matched the target and held steady rather than settling straight back down.
Outcome
Cooling came back to where it should have been from the start, and the CH38 code has not returned since. No parts were replaced, and no leak was ever found.
What this case teaches us
CH38 on a brand-new unit does not automatically mean a leak
- A low-refrigerant code like CH38 can mean gas escaping. On a unit only weeks old, it can just as easily mean the charge was never completed correctly at install.
- A pressure check plus a leak sweep across every joint can rule out an active leak before assuming one exists. That keeps the fix to a charge instead of a repair.
- Ask whether the line was fully evacuated and charged to the right level at install. That step done properly is what a working CH38 fix depends on.
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