Portable unit not cooling traced to kinked exhaust and recirculation
Aircon case in Bukit Merah, Singapore: airflow traced to exhaust hose kinked against the wall behind the unit — heat could not exit the room, recirculated back to intake after targeted diagnosis checks.
Case details
What client reported
The customer said the unit had run for three to four hours but the room never dropped below 30°C. The back of the unit felt warm and the compressor sounded strained. It had worked fine for two years until a furniture rearrangement a month ago.
What we found
The furniture move was the key detail — we checked unit placement and hose routing first
- Unit back was about 5 cm from the wall — hose could not exit without bending
- Exhaust hose had a tight kink at the rear — hose opening reduced to about 20% of normal
- Air at the back of the unit was much warmer than ambient — hot exhaust was venting back into the room
- Compressor, fan, and refrigerant circuit all normal when the hose was straightened and heat could exit
The furniture move had pushed the unit close to the wall, which kinked the exhaust hose. Hot air could not leave the room. The unit was working correctly. The only problem was the hose routing.
What we did
The unit was moved 30 cm from the wall. The exhaust hose was straightened to a gentle upward run to the window vent. The room dropped by 4°C within 20 minutes. No parts were needed — the fix was the position.
The unit has cooled normally since it was repositioned. The customer was told to keep 30 cm of clearance behind the unit and check the hose when moving furniture. The hose should also be checked from time to time as it can kink if pushed against a wall.
Timeline
Day 1
Unit running continuously but room not cooling — customer reported compressor sounding laboured
Day 1
Checked hose routing on arrival — hose had a 180-degree kink where it was pressed between the unit and the wall, hot air from the exhaust was venting back into the room
Day 1
Exhaust hose kink found, unit moved 30 cm from wall, hose straightened, room temperature dropped within 20 minutes
What we learned
Why portable units need clear exhaust routing.
- A portable unit cools a room by pulling heat out of the air and pushing it away through the exhaust hose. If that heat cannot leave the room, it goes straight back into the air the unit is trying to cool.
- A kinked or blocked exhaust hose traps that heat inside. The unit runs at full load fighting its own waste heat on top of the normal room heat.
- Hot air from a kinked hose vents near the back of the unit, which sits close to the intake. This creates a direct loop — the unit cools air and immediately re-heats it.
- Correct hose routing means a straight or gently curved run to a window vent. No kinks, no tight bends, and at least 30 cm of clearance between the back of the unit and any wall.
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