Aircon Refrigerant System
Refrigerant is the fluid that moves heat out of your room. When it leaks, cooling drops. But a top-up without a leak check just delays the same problem. We find the source first.
What This Part Does
Refrigerant is the working fluid inside your aircon. It circulates in a closed loop between the indoor and outdoor unit, absorbing heat from your room and releasing it outside.
It does not get used up during normal operation. A well-sealed system holds the same refrigerant charge for the life of the unit. If the level drops, something has caused it to leak out.
When the charge drops low, the system cannot absorb heat efficiently. The room stays warm even though the aircon is running. Left too low, the compressor runs hot and can be damaged.
How You Would Notice
The most common sign is gradual cooling loss. The unit cools well initially, then performance drops over weeks or months. The room takes longer to reach temperature and never gets as cold as it used to.
Ice forming on the indoor coil or the pipe running to the outdoor unit is a strong sign of low refrigerant. The coil gets too cold without enough refrigerant pressure and moisture in the air freezes on it.
In some cases the outdoor unit runs constantly without the room cooling. You may also notice a hissing sound near the indoor unit — refrigerant escaping under pressure.
- Gradual decline in cooling over weeks or months
- Ice visible on the indoor coil or refrigerant pipe
- Unit runs constantly without reaching set temperature
It Might Not Be The Refrigerant
A dirty coil, blocked filter, or weak fan motor cause the same gradual cooling loss. Before attributing poor cooling to low gas, airflow and coil condition need to be confirmed.
A failing expansion valve causes inconsistent cooling and can look like a gas issue. The valve controls how refrigerant enters the indoor coil — when it drifts, refrigerant distribution becomes uneven.
A top-up without a pressure check and leak test just adds gas to a system that will lose it again. It does not fix anything.
How We Check
We start with system pressure. A pressure reading tells us whether the charge is within the correct range for that unit and refrigerant type. This is the baseline before anything else.
If pressure is low, we do a leak test before adding gas. We check the common leak points — joints, the service valves, the indoor coil, and the connecting pipes. Leaks at joints or valves can often be sealed. Leaks at the coil or compressor are a different problem.
If the system holds pressure correctly and cooling is still poor, the cause is elsewhere — not refrigerant. We move to coil condition, airflow, and expansion valve.
We only top up after the leak source is found and addressed. A top-up into an active leak is a short-term fix that leads to the same call a few months later.
What We Find And What Happens Next
Most cases fall into one of three outcomes. Pressure is fine and the issue is elsewhere. Pressure is low with a repairable leak. Or pressure is low with a leak at a component that needs replacement.
| Finding | Next Step |
|---|---|
| Pressure within range, cooling still poor | Check coil, airflow, expansion valve |
| Pressure low, leak at joint or valve | Seal leak, top up, retest |
| Pressure low, leak at coil or compressor | Component assessment — top-up not advised |
About The Repair
A simple top-up after a sealed joint leak is a minor job. The result should be immediate — cooling returns to normal once the system is back at the correct charge.
Leaks at the indoor coil or compressor are more involved. Coil replacement requires partial disassembly of the indoor unit. A compressor with a refrigerant leak at its seals is typically a sign the compressor is nearing end of life.
If a technician recommends a top-up without mentioning a leak check, ask whether they tested system pressure and where the gas went. Refrigerant does not disappear on its own.
After Replacement
After a top-up or leak repair, we run the system to confirm pressure holds and cooling returns to normal. A system that holds charge should behave as it did when the unit was new.
If pressure drops again within a short period after a confirmed top-up, there is a second leak point that was not found. The system needs to be retested, not just refilled.
We note the refrigerant type used and confirm compatibility with the unit's specification. Using the wrong refrigerant type causes system damage and is not reversible without a full flush.
When We Tell You To Wait
If the unit is still cooling and pressure is borderline rather than clearly low, monitoring is reasonable. A borderline reading may reflect a gradual leak or the unit's age and efficiency loss.
We will tell you the reading, what the correct range is, and what the gap means in practical terms. You can make an informed decision rather than act on a vague recommendation.
If ice is forming on the coil or pipe, do not wait. Turn the unit off and contact us. Running a unit in that state stresses the compressor.