Condo ran warm after install: line not purged first
A riverside condo near Robertson Quay had a new unit installed that never quite cooled properly, from the very first week. New installations here often work through a tight, converted service void, where a rushed purge step leaves no visible evidence once the system is charged.
By Team Snowflake | Updated 28 Jul 2026
Case summary
LG Wall-mounted2 years oldCondoSingapore River, Singapore
- Concern
- The homeowner suspected a defective new unit and considered asking for a full replacement under warranty.
- Found
- Refrigerant line not fully purged of air before charging, reducing cooling capacity from day one
- Key check
- Checked the system's actual refrigerant condition against installation records before assuming a unit defect
- Result
- The unit reached its set temperature at the expected speed once the line was properly purged and recharged. The homeowner avoided pursuing a warranty replacement for a unit that was never actually defective.
What we were told
The unit had never cooled the way a brand-new system should, even on the first day it was switched on, and no setting change made a difference. The room reached a comfortable temperature eventually but took far longer than expected, and never felt as cold as the showroom promised. The unit had been installed through a narrow service void shared with an older building riser.
What we checked
Day-one underperformance was the key clue, not a defective unit. A factory fault would usually show something more obvious than gradual, mild underperformance, so the install itself came under scrutiny first. We checked the refrigerant condition against what a correctly purged and charged system should read.
The unit itself powered on and ran normally with no fault codes.
Refrigerant pressure readings were consistent with air trapped in the line alongside the refrigerant charge.
The pipe run through the narrow service void left limited room to fully vent the line before charging.
No leaks were found anywhere along the accessible pipe run.
What we found
The service void's tight access made it difficult to fully purge air from the refrigerant line before the system was charged. A small amount of trapped air mixed with the refrigerant, which reduces how efficiently the system can absorb and reject heat. The unit was never faulty; it had simply been operating with a compromised charge since the day it was switched on, which is why performance never matched a normal new installation.
What fixed it
We recovered the existing charge, properly evacuated and purged the line, and recharged it to the correct amount for the unit. We advised the homeowner to ask any future installer working through a tight service void to confirm the evacuation step specifically, rather than assuming it was done.
Outcome
The unit reached its set temperature at the expected speed once the line was properly purged and recharged. The homeowner avoided pursuing a warranty replacement for a unit that was never actually defective.
What this case teaches us
A new unit that never cooled well points at the install, not the unit
- If a system has never cooled properly since day one, the install itself is a more likely cause than a defective unit.
- A cramped or converted service void can make it easy to rush the purge step before charging.
- Ask whether the line was pressure-tested and purged of air before the refrigerant charge was added, especially after a tight-access install.
Questions this case answers
Can a new aircon underperform from day one without being faulty?
How does air get left in a refrigerant line during installation?
What happens if trapped air is never removed from the line?
Can I ask for this step to be confirmed on a tight-access install?
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Tell us what’s going on. Symptoms, setup, photos, anything we should know. We’ll assess and come back with the right next step.