Aircon refrigerant system

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.

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.

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.

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.

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.

The signal is weak cooling that develops slowly despite normal system operation.

Refrigerant loss from leaks causes progressive cooling decline.

Once refrigerant is lost, the system cannot function properly regardless of other parts.

When cooling gradually worsens with normal electrical operation, refrigerant pressure testing is needed.

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.