LG CH38 in one bedroom only: pinhole leak inside that room's indoor coil
LG's CH38 code flags low refrigerant pressure, and repeated appearances usually mean a leak somewhere in the system. On this Yishun condo's multi-split, only one bedroom lost cooling while every other room ran normally, which pointed the search away from the shared outdoor unit.
By Team Snowflake | Reviewed 11 Jul 2026
Case summary
LG Multi-split8 years oldCondoYishun, Singapore
- Concern
- The homeowner worried the whole outdoor system was failing, or that an earlier top-up simply hadn't been enough gas
- Previous advice
- Homeowner assumed the shared outdoor system was failing, or that an earlier top-up had not been enough
- Found
- Pinhole leak in the affected bedroom's own indoor coil, unrelated to the outdoor unit or any joint
- Key check
- Confirmed the other rooms on the same outdoor unit stayed cold, then traced the affected bedroom's own dedicated line before finding the pinhole on the coil itself
- Result
- Cooling returned to that bedroom within minutes of the recharge, and it has held steady since. The CH38 code cleared, and the other two rooms were never touched.
What we were told
One bedroom kept blowing warm air and showing the CH38 code, while the living room and the other bedroom stayed cold as usual. The unit had been topped up once before. The homeowner assumed the whole outdoor system, shared across all three rooms, was starting to fail.
What we checked
Only one room losing cooling on a shared system usually points at that room's own line. It rarely means the shared outdoor unit itself is failing. We checked gas pressure at the affected bedroom first to confirm an active leak. From there we worked outward along that room's own dedicated line, before touching anything the other rooms shared.
Gas pressure at the bedroom unit read low, while the other two rooms measured normal pressure on their own lines.
The other two indoor units, running off the same shared outdoor unit, cooled normally throughout, which ruled out a shared fault.
Tracing the bedroom's own line back from the indoor unit found no leak at any joint, valve, or fitting along the run.
A closer check of the bedroom coil itself found a small pinhole low on one row, the source of the slow leak.
What we found
Each indoor unit on a multi-split runs its own separate line back to the outdoor unit, so a leak on one line only affects that room. A pinhole had opened directly in the bedroom coil itself, not at any joint or fitting, from ordinary long-term wear. It was slow and hard to spot, letting gas seep out gradually. That is why CH38 kept showing in that one room while the other two, each on their own line, kept cooling normally.
What fixed it
We isolated the section of coil with the pinhole and replaced just that part, rather than the whole indoor unit or the outdoor system. The rest of the bedroom coil, and both other indoor units, were sound and did not need touching. Once the new coil section was fitted, we recharged that room's line to the correct level and pressure-tested it on its own before closing the unit back up.
Outcome
Cooling returned to that bedroom within minutes of the recharge, and it has held steady since. The CH38 code cleared, and the other two rooms were never touched.
What this case teaches us
On a multi-split, one room's fault is usually that room's own line
- Each indoor unit on a multi-split has its own line to the outdoor unit. If only one room stops cooling while the rest keep working, the fault usually sits on that room's line alone.
- A leak does not always sit at a joint or fitting. It can open directly in the indoor coil itself, which makes it harder to trace.
- Ask which room is affected before agreeing to any system-wide work. One warm room on a shared system usually points to a fix in that coil, not a bigger repair.
Related reading
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