AC smells sour after heavy rain: water ingress, odor sources and shut-down inspection
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If the AC smells sour after a typhoon or heavy rain, that does not mean rainwater has caused acidic scale or the growth of specific microorganisms inside the unit. First distinguish between water ingress, drainage abnormalities, and other sources from the equipment or the room; if water ingress is suspected, stop using it and do not keep switching it on just to smell, dry, or dehumidify it.
Safety comes before odour removal
Do not touch damp electrical parts, do not open the casing, and do not lean out to look at the outdoor unit. A suitable person should confirm the moisture condition and power supply status. Simply waiting for the casing to dry, the rain to stop, or some time to pass does not guarantee it is safe to switch on.
Provide the time and location of the odour.
Record whether the same odour appeared before the rain, how long after switching on it appeared, which area is more noticeable, and whether there is any dripping, unusual noise, breaker tripping or poor cooling. Odour cannot be used to measure acidity or alkalinity, bacteria levels, or determine whether the circuitry is normal. Do not collect dirty water from inside the unit yourself.
Cleaning and repairs each have their own scope
After confirming the type of buildup that can be handled, only then discuss the cleaning area, products and surrounding protection. Drainage pipes, insulation, external wall seepage or electrical faults may not be covered in the same cleaning service. We do not promise that a water jet or chemicals can eliminate all causes of odour.
How should lingering odour be followed up after completion?
Keep the records of the treatment carried out and when the issue appeared again so staff can check for the source or other unaddressed problems. Do not spray fragrance, strong acid or alkali, or use higher water pressure to cover up odours, and do not assume the equipment will never have problems again just because one test-run had no smell.
Related reading and services
- Related service scope and current charges
- Back to AC encyclopedia
- Daikin: operating and safety manual for specified split-unit models
- Daikin: cleaning, operation and fault-handling guide
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