Why Mitsubishi aircon not cold
A Mitsubishi aircon not cold issue is a common problem faced by many homeowners in Singapore. When your air conditioner is switched on but fails to cool the room properly, it usually indicates reduced efficiency or an internal fault within the system. Ignoring early signs can lead to higher electricity bills and costly repairs. At LetsCool Aircon, we diagnose and fix Mitsubishi aircon cooling problems daily, helping customers restore strong and consistent cooling quickly.
Reasons of Mitsubishi Air Conditioner Not Cooling ?
A Mitsubishi aircon that is not cooling properly does not always mean a major breakdown. Many cooling problems are caused by maintenance-related or technical issues that can be resolved with timely servicing. Below are the key causes of Mitsubishi aircon cooling problems and how professional aircon servicing can help.
1. Dirty Air Filters – Blocking Air flow
Air filters trap dust, dirt, and pollutants. When they are clogged, cold air cannot flow smoothly into your room.
Common signs:
- Weak airflow
- Air feels slightly cool but not strong
- Higher electricity usage
Cleaning your filters every 2–4 weeks is essential in Singapore’s dusty and humid environment.
2. Fan Coil Unit Is Dirty Inside
Even if filters are clean, dust and mould can build up deep inside the fan coil unit.
What happens:
- Cooling becomes slow
- Air smells unpleasant
- Water leakage may occur
Regular professional air conditioning servicing is needed to fully clean internal components.
3. Low Refrigerant (Gas) Level
If your Mitsubishi aircon blows air but never becomes cold, low gas pressure is a major cause.
Reasons gas becomes low:
- Refrigerant gas leak
- Poor installation
- Old copper piping
Simply topping up gas without fixing leaks will cause the problem to return.
4. Outdoor Condenser Is Dirty or Overheating
The outdoor unit releases heat from your room. When it is dirty or blocked, heat cannot escape properly.
Result:
- Poor cooling performance
- Aircon feels warm during the daytime
- System strains and uses more power
Condenser cleaning or chemical wash restores proper heat release.
5. Faulty Thermostat or Sensor
If the temperature sensor is faulty, your aircon may think the room is already cold and reduce cooling.
Symptoms:
- Aircon stops cooling too soon
- Inconsistent room temperature
- Cooling works only intermittently
Professional inspection is required to recalibrate or replace sensors.
Refer: Aircon Repair
6. Electrical Component Issues
Mitsubishi aircon units rely on components like capacitors and PCB boards.
Possible problems include:
- Aircon turns on but does not cool
- Blinking lights or error codes
- Sudden shutdowns
These issues should only be handled by trained technicians to avoid further damage.
7. Incorrect Aircon Size for the Room
An aircon that is too small for your room will never cool efficiently.
Common mistakes:
- Low BTU unit for large rooms
- One indoor unit serving multiple spaces
A proper site survey ensures correct aircon capacity for your space.
8. Poor or Aging Installation Piping
Old or badly installed copper piping can cause gas leaks and cooling loss.
Signs:
- Repeated gas top-ups
- Cooling improves briefly then fails again
Replacing old piping can permanently solve recurring cooling issues.
9. Lack of Regular Maintenance
Without regular servicing:
- Dust builds up
- Gas pressure drops
- Components wear out faster
For Singapore homes, Mitsubishi aircon should be serviced every 3–6 months.
How Much Cost to Fix Mitsubishi Aircon Not Cooling?
The cost to fix a Mitsubishi aircon not cooling in Singapore depends on the root cause of the problem. Simple maintenance issues are usually affordable, while technical faults or major component replacements may cost more. Early diagnosis always helps reduce repair expenses.
Below is a general price guide to help you understand what to expect:
Estimated Cost to Fix Mitsubishi Aircon Cooling Issues in Singapore
General aircon servicing:
If cooling is weak due to dust buildup, a standard servicing usually solves the problem.
💰 Estimated cost: $30 per unit
Aircon Chemical wash (fan coil or condenser):
Recommended when internal components are heavily clogged or mouldy.
💰 Estimated cost: $60 per unit
Refrigerant (gas) top-up:
Needed when gas pressure is low. Prices depend on system size and gas type.
💰 Estimated cost: $80 – $150
⚠️ Leak testing may be required before topping up gas.
Aircon gas leak repair:
If there is a refrigerant leak, repairs are required before refilling gas.
💰 Estimated cost: $150 – $350 (depending on leak location)
Thermostat or sensor replacement:
Faulty sensors can cause inconsistent or weak cooling.
💰 Estimated cost: $90 – $150
PCB board or electrical component repair:
Required when cooling stops due to electrical faults or error codes.
💰 Estimated cost: $250 – $600 (model-dependent)
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When Should You Clean Your Mitsubishi Aircon to Avoid Cooling Issues?
Regular cleaning is one of the most effective ways to prevent Mitsubishi aircon cooling problems. In Singapore’s hot, humid, and dusty environment, aircon units collect dirt much faster than expected. If cleaning is delayed, airflow becomes restricted and cooling efficiency drops.
Recommended Cleaning Frequency in Singapore
Every 2–4 weeks: Clean the air filters :
Air filters trap dust and airborne particles. When they are dirty, cool air cannot pass through properly. Regular filter cleaning helps maintain strong airflow and consistent cooling.
Every 3–6 months: Professional aircon servicing :
Even if the filters look clean, dust, mould, and bacteria can build up inside the fan coil unit. Professional servicing removes hidden dirt that normal cleaning cannot reach.
Every 6–12 months: Deep cleaning or chemical wash (if needed) :
If cooling is slow, airflow is weak, or there is a bad smell, a chemical wash may be required. This restores cooling performance and prevents long-term damage.
Why Choose Letscool For Mitsubishi Aircon Water Leaks
At Letscool Aircon, we specialise in Mitsubishi aircon servicing and repairs across Singapore.
- Experienced Aircon technicians
- Proper diagnosis (no guessing)
- Transparent Servicing price
We fix the root cause, not just the symptom.
Conclusion
A Mitsubishi aircon not cold is usually caused by dirty components, gas issues, electrical faults, or incorrect sizing. With timely servicing and professional care, your unit can cool efficiently again.
