If your AC runs but doesn’t cool, first check the mode, the filter, the power and the airflow around the outdoor unit. If those are fine, the fault is likely a refrigerant leak, a failed capacitor, a stopped fan or the compressor, which is work for an AC repair technician.
Quick checks you can safely do yourself
1. Wrong mode or temperature setting
Samsung lists wrong settings among the causes of poor cooling:
- Set the remote to Cool, not Fan or Dry. On models that heat, Heat mode explains an AC blowing warm air.
- Set a temperature below room temperature and check that no off-timer is active.
2. A clogged filter
A dirty filter chokes airflow, so the AC cools poorly and the indoor coil can freeze. Daikin, LG, the Saudi Energy Efficiency Center (SEEC) and the Saudi Electricity Company (SEC) advise cleaning filters every two weeks in the cooling season; Gree says every three months, more often in dusty conditions.
- Switch off the power and slide the filters out.
- Rinse them, let them dry fully and refit.
Full steps: our split AC cleaning guide.
3. Power: the breaker and the 3-minute delay
Outdoor unit silent while the indoor unit blows? Not necessarily a fault:
- Wait three minutes. Daikin notes that after the AC is switched off or the mode is changed, the outdoor unit restarts only after a delay of about three minutes.
- Check the breaker. The outdoor unit may have its own, which may have tripped.
- If it trips again, stop: that’s an electrical fault for a technician.
4. A blocked or boxed-in outdoor unit
The outdoor unit dumps heat outside. Obstructions, covers or a narrow light well where it re-breathes its own hot air all cut cooling. SEEC advises against installing ACs in light wells, and SEC recommends shading the outdoor unit.
- Clear obstructions and remove any cover.
- Shade it without blocking the air outlet.
- Keep curtains and furniture clear of the indoor unit.
Still not cooling? Send technician Ali at Mousa Workshop a photo of the outdoor unit or the error code on WhatsApp, or call +966 54 372 8453. We diagnose first and tell you the cost before starting.
Causes that need a technician
Safety first: don’t open the outdoor unit or the electrical box. Capacitors hold a dangerous charge even when switched off, and refrigerant work needs proper tools and training.
5. Refrigerant leak (low gas)
Refrigerant isn’t used up in a sealed system, so low gas means a leak. Signs include air that isn’t cold, higher indoor humidity, uneven cooling, rising bills and sometimes hissing or ice on the coil. The fix is to repair the leak and then recharge, not just top up. See the signs your AC is low on refrigerant.
6. Failed capacitor
The capacitor helps the compressor and fan motors start. Signs of failure:
- The unit runs, but the air isn’t cold.
- Loud humming from the outdoor unit.
- Short cycling: on and off within minutes.
- A burning smell, or a bulging, cracked or leaking capacitor.
Replacement is routine for a technician, but the stored charge makes it dangerous for anyone else.
7. Outdoor fan not spinning
If the outdoor fan stops, pressure builds and the unit trips or cools weakly. A fan that hums but won’t turn usually means a failed capacitor, or else a burnt-out motor or a tripped breaker. Never try to start the blades by hand or with a stick.
8. Dirty outdoor or indoor coil
Shamal dust, and salt air near the sea, clog the outdoor (condenser) coil so it can’t shed heat. Gree’s E1 high-pressure protection code is linked to dirty coils and high outdoor heat. A dirty indoor coil restricts airflow and can ice up. The fix is a proper indoor and outdoor AC cleaning.
9. Compressor fault
If the outdoor fan turns but the air stays warm, the compressor may not be running. Before condemning it, a technician rules out cheaper parts such as the capacitor and contactor, then measures current and pressures. On Gree units, H3 means compressor overload protection.
10. Faulty sensor or control board
A faulty room or coil sensor can cut the compressor early or trigger a code: F1/F2 on Gree, CH01/CH02 on LG. Indoor–outdoor communication faults typically show as E6 on Gree or CH05 on LG. Codes vary by model, so check your manual and our split AC error codes guide.
Why is my AC not cooling? Quick diagnosis table
| Symptom | Likely cause | Who fixes it? |
|---|---|---|
| Warm air | Fan or Heat mode, or compressor not running | You, then technician |
| Outdoor unit silent | 3-minute delay, tripped breaker, electrical fault | You, then technician |
| Outdoor fan hums, won’t spin | Failed capacitor or burnt motor | Technician only |
| Weak airflow | Dirty filter or indoor coil | You (filter), technician (deep clean) |
| Ice on the pipes | Dirty filter, blocked return air, refrigerant leak | Fan only, then technician |
| Weak only at midday | Dirty outdoor coil, direct sun, undersized unit | Shade it, then technician |
| No cooling, no drain water | Refrigeration cycle not running | Technician |
| Error code | Protection, sensor or communication fault | Manual, then technician |
AC not cooling and no water dripping
A properly cooling AC drains condensed water in humid weather. If the cooling and the water both stop, the refrigeration cycle has probably stopped: the compressor isn’t starting, the capacitor has failed or the refrigerant is very low. Call a technician.
Ice on the AC pipes: switch off, don’t chip it
Ice on the pipes or indoor unit signals a fault, not ‘strong cooling’. Trane lists the causes: a dirty filter or evaporator coil, blocked return vents, a faulty thermostat or a refrigerant leak.
- Switch cooling off and run the fan only until the ice melts.
- Don’t chip it: you could puncture the coil or pipe.
- Clean the filter. If the ice returns within days, call a technician.
Put a towel below the unit for the meltwater. Some Gree models show E2 when indoor anti-freeze protection activates.
AC not cooling in the afternoon: Eastern Province heat and unit size
Dammam’s average daily highs are about 44°C in June and 45°C in July and August, and in June 2026 the National Center for Meteorology warned of 47–48°C with dusty winds across the province, including Qatif. Samsung lists extreme outdoor heat among the causes of weak cooling, and small weaknesses, like a dusty coil or slight gas shortage, show first at midday.
The unit may also be too small. SEC’s rule of thumb is about 800 BTU per m² for uninsulated buildings and 600 BTU per m² for insulated ones, so a 20 m² uninsulated room needs roughly 16,000 BTU: an 18,000 BTU unit, not a 12,000.
- Shade the outdoor unit and have its coil cleaned before summer and after the dust season.
- Use insulating curtains and seal gaps around doors and windows, as SEEC advises.
When to call a technician
- The quick checks haven’t helped.
- Ice returns after you’ve cleaned the filter.
- The outdoor unit hums or its fan won’t turn.
- An error code keeps returning.
- You smell burning or the breaker keeps tripping: switch the AC off immediately.
At Mousa Workshop in Al-Salam District, Saihat, technician Ali diagnoses the fault first and tells you the cost before starting. We’re open daily from 8 AM to 11 PM across Saihat, Anak, Qatif, Tarout, Dammam, Khobar and Safwa. Book AC repair in Saihat, Qatif or Dammam by WhatsApp or phone.
Sources
Frequently asked questions
Should I keep running my AC if it isn't cooling?
Not for long if the outdoor fan has stopped or you suspect a refrigerant leak, because running it that way strains the compressor. It's better to switch it off until the cause has been checked and fixed.
Why is my new AC not cooling after installation?
Common reasons are a unit too small for the room, an outdoor unit squeezed into a narrow light well or baking in direct sun, or an installation done without evacuating the pipes. Installation manuals warn that air or foreign matter left in the circuit causes abnormally high pressure.
What temperature should I set my AC to in summer?
The Saudi Energy Efficiency Center recommends 24°C and the Saudi Electricity Company recommends 25°C. Setting it much lower won't cure weak cooling — it only lengthens run time and raises the bill.
Are the causes different for an inverter AC?
They're largely the same: dirty filters and coils, low refrigerant, fans and sensors. Inverter units add an electronic compressor drive (IPM) that can fail, typically flagged by codes such as H5 on Gree or CH21 on LG, depending on the model.