Troubleshooting
Aircon Not Cold? Causes, Gas Leak Checks & Repair Costs
An air conditioner that is working but not providing cool airflow is most likely one of these seven things. Some you can fix right away within ten minutes, others require professional help. Here is how to identify the cause and fix it yourself before your repair guy charges you.
First, rule out the easy fixes
Humid weather, open doors, or even running ceiling fans with the aircon can make a room feel uncool. Close the doors and wait about half an hour before deciding anything.
- Check and switch the setting from Fan or Dry to Cool
- The temperature setting is higher than room temperature
- The fan speed is on Auto and the unit is in low-demand mode
- There may be a window or door that is open, or the room gets direct afternoon sun
1. Clogged filters, easily the most frequent reason
Filters get dirty after just four to six weeks in our climate. Blockage reduces airflow, which lets the coil freeze, and the air that comes out is only tepid at best.
Remove the filter by pushing it out, rinse under water, dry completely and put it back. If you feel an immediate improvement in the air coming out, you have found the culprit, and your servicing schedule is simply too long.
2. A frozen evaporator coil
To defrost the ice on the coil, switch the aircon from Cool to Fan for 30 to 60 minutes.
Freezing is an indicator and not a root problem. It occurs when there is no airflow, the coil is dirty, or refrigerant is low. Book a chemical wash or gas check if it freezes again after defrosting.
3. Low Refrigerant: Gas Leak / Piping Work / Refill
Aircon gas does not reduce on its own, so the reason for low gas is always a leak somewhere in the system. Symptoms are ice on the thin copper pipe at the outdoor unit, a hissing sound, and cooling that gradually deteriorates from one level to another over weeks.
A gas top-up is a temporary solution. A real fix involves pressure-testing, leak detection, and patching the leak; after the patching, the system is reloaded with gas. If the leak is in the refrigerant piping, that section may have to be repaired or replaced entirely before the system is reloaded. Anyone who refills without checking for leakage is selling you the same service again three months later.
Problematic Refrigerant Piping and Installation Matters
Between the indoor and outdoor units, refrigerant runs through copper piping. Joint cracks, damaged pipes, incorrect flare connections and improper piping installation lead to refrigerant loss and insufficient cooling. The signs are ice on the copper pipe, weak cooling performance and the need for repeated gas refills. A specialist should pressure-test the piping, repair or replace the broken section where applicable, and finally recharge the system with the right refrigerant.
4. A dirty condenser (outdoor unit)
We get rid of the heat through the outdoor unit. If dirt, leaves or bird droppings are sticking to the fins, the outdoor unit struggles to dump heat and the entire aircon system cannot function at full capacity.
Leave at least 30cm of space around the unit and ensure nothing interrupts the flow of the fan discharge.
5. A faulty compressor or capacitor
When the outdoor fan is running but the compressor is not starting, or the unit makes a humming sound and then trips, a run capacitor is the most probable and cheapest cause.
Replacing a genuinely damaged compressor on a system a few years old may cost more than the whole unit is worth. From that point, a new system will be suggested instead.
6. Undersized or overloaded system
A 9,000 BTU aircon will be of no use for a big living room, and a System 3 running all four rooms at the same time will underperform if it was designed for only two rooms.
If the system has never produced satisfactory cooling since the first day of use, the mistake was made with the size of the unit rather than any technical fault.
7. Blocked drainage causing a safety cut-out
Most units have a float switch that stops cooling when the water level in the drain pan rises to a certain point.
If the drainage line is clogged, the fan keeps rotating so the unit still gives the impression of working while producing no cold air at all. Cooling is restored after clearing the drain line.
Estimate of each repair cost
We always give a quotation before starting any work. We will be honest with you if a repair is too expensive. That will be our suggestion, rather than pushing you from one sales offer to another.
Frequently asked questions
How often should I service my aircon in Singapore?
Every three to four months for a home used daily. Our 3-times-yearly contract covers that interval and includes a free mattress cleaning.
Does topping up gas fix an aircon that isn't cold?
Only if refrigerant is genuinely low, and only until the leak empties it again. Always insist on a leak test with any top-up.
How much does an aircon gas top-up cost in Singapore?
The price depends on the refrigerant type, the amount of gas required, the system size and whether a leak must be repaired first. We inspect the aircon, confirm the cause of low cooling and provide a quotation before starting any gas top-up or refill work.
Is an aircon gas refill the same as a Freon refill?
Yes. Freon is a common name for aircon refrigerant, so a Freon refill and a gas refill usually refer to the same service. The correct refrigerant type depends on the aircon model and must be confirmed before topping up.
Why is my aircon cold at night but not in the afternoon?
Heat load. If the system is marginally sized, it copes overnight but cannot keep up against afternoon sun. Servicing restores lost capacity; if it still struggles, the unit is undersized.
Need help with this? Message us. We quote before we start.
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