Common Air Conditioning Problems and What They Mean

It runs but does not cool

Usually airflow or refrigerant. Check the filters first — a blocked filter is the most common cause by a wide margin. Then check the outdoor unit is not obstructed and the fan is spinning.

If both are fine, suspect low refrigerant from a leak, which needs an engineer with recovery equipment and leak detection, not a top-up.

Water dripping from the indoor unit

Almost always condensate drainage: a blocked drain, a slipped or sagging drain line, a failed condensate pump or a tray full of biological growth.

Turn the unit off to stop making more water and get it looked at promptly — this is the fault that damages plaster and flooring.

Musty or sour smells

Biological growth on the coil or in the drain tray. A deep clean at service usually resolves it. Running the unit in fan mode for a few minutes after cooling helps dry the coil and prevents recurrence.

A burning smell is different — turn it off and call us.

Ice, noises and error codes

Ice on the pipework indicates restricted airflow or low refrigerant. Rattles are often loose panels or brackets; grinding or screeching points at a fan bearing or compressor and should be investigated immediately.

Error codes are manufacturer specific — photograph the display and tell us the code, it usually shortens diagnosis considerably.

• Ice on pipes → airflow or charge problem
• Rattle → loose panel, bracket or debris
• Grinding → mechanical, stop using it
• Code on display → note it before resetting

When to stop and call someone

Any burning smell, tripping breaker, visible damage, oily residue around pipework or grinding noise means switch off and call. Refrigerant work and electrical work are not DIY.

Filters, obstructions and remote batteries are fair game. Everything past that needs an F-Gas qualified engineer.