An air conditioner is a lifesaver on hot days, but what if instead of the long-awaited coolness, it blows warm air? The problem can be as simple as forgetfulness (such as setting the wrong mode) or as serious as a major breakdown. In this guide, we have covered 10 main reasons why the air conditioner is not cooling. You will also find tips on how to fix the issue yourself or when it’s time to call a technician.
1. Dirty Air Filters
Symptoms:
- Weak airflow.
- The air conditioner is running at maximum, but the room isn’t cooling.
Solution:
- Remove the front panel of the indoor unit.
- Take out the filters and rinse them under warm water (photo of the process below).
- Dry and reinstall them.
Tip: In hot weather, clean the filters every 2 weeks to prevent system overload.
2. Refrigerant (Freon) Leak
Signs of a leak:
- Frost on the copper pipes of the outdoor unit.
- Hissing noise during operation.
- The air conditioner blows air but doesn’t cool even after long operation.
What to do:
- Check system pressure using a manifold gauge set (professional equipment).
- Found a leak? Do not attempt to refill Freon yourself—it is dangerous and requires a license. Call a service technician.
3. Incorrect Mode Settings
Typical situations:
- Heating mode (“Heat”) is on instead of cooling (“Cool”).
- Temperature is set too high (e.g., 28°C while it’s 35°C outside).
Solution:
- Switch the mode to “Cool” (snowflake ❄️).
- Set the temperature 5–7°C lower than the outdoor temperature for a safe difference.
4. Clogged Drain System
Symptoms:
- Water leaking inside the room.
- Moldy smell appears.
How to fix:
- Turn off the air conditioner from the power supply.
- Blow out the drain pipe with a vacuum cleaner or clean it with a flexible wire.
- Treat the system with an antibacterial agent.
Tip: Regular drain cleaning prevents flooding and bacterial growth.
5. Compressor Malfunction
Signs of failure:
- Humming noise from the outdoor unit without cooling.
- Frequent spontaneous shutdowns.
Causes:
- Worn parts.
- Overheating due to a clogged fan.
- Voltage surges.
Recommendation: The compressor is the “heart” of the air conditioner. Replacement should only be done through a service center.
6. Dirty Outdoor Unit
Why it happens:
- Fluff, leaves, and dust clog the grill, disrupting heat exchange.
Solution:
- Disconnect the power.
- Carefully clean the outdoor unit with a brush (if easily accessible).
7. Fan Failure
How to identify:
- Strong vibration or noise.
- Blades not spinning.
What to do:
- Check if the impeller is jammed by debris.
- If the motor is burned out—replacement is needed. You can’t do it without calling a technician.
8. Electronics Malfunction
Examples of errors:
- Codes E1, E2 on the display.
- Spontaneous shutdowns.
Solution:
- Reboot the system: unplug for 10 minutes.
- Didn’t help? Contact service for board diagnostics.
9. Insufficient Air Conditioner Capacity
Why it matters:
- A split system designed for 20 m² can’t handle 40 m²!
Tip: Calculate the required power using the formula:
Power (BTU) = Room area (m²) × 337 + 10% reserve.
10. Clogged Capillary Tube
Symptoms:
- Ice on the evaporator.
- Compressor overheating.
Solution:
- Professional system flushing with special solvents is required.
When to Call a Technician:
- The air conditioner makes a loud noise or smells like burning.
- Frost appears on the pipes.
- After all manipulations, the split system still does not cool.
Don’t take risks! Repairs under high pressure are dangerous for beginners.
Preventive Maintenance
✅ Annual maintenance before the summer season.
✅ Installation of a voltage stabilizer.
✅ Protect the outdoor unit with a cover to prevent debris.
If you are located in San Diego and experiencing air conditioner issues, contact us. Omega Tech service specialists will provide professional maintenance or repair of your air conditioner in the shortest possible time.
FAQ
- Why does the air conditioner blow but not cool?
Most often dirty filters or a refrigerant leak are to blame. - Can I refill the Freon myself?
No! Refilling requires equipment and a license. - How can I tell if the compressor is broken?
The air conditioner hums but does not cool, and there is frost on the pipes.
Conclusion
Most cooling problems are solved by cleaning the filters and checking the settings. However, if you encounter a refrigerant leak or compressor failure — don’t experiment! Trust the repair to professionals to avoid costly consequences.
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