Hisense Aircon Gas Top Up and Refrigerant Leak Repair

Plenty of owners ring up asking for a quick regas because the bedroom split system has gone lukewarm. It sounds like a simple refill, much like topping up a car with fuel. In reality, refrigerant does not burn off or wear out, so a system that is short on gas has almost always sprung a leak somewhere.

That is why a proper Hisense aircon gas top up is really a leak job first and a recharge second. A licensed refrigeration technician finds where the gas escaped, repairs that point, proves the circuit holds pressure and only then puts the correct charge back in. This page explains each stage, what you can check yourself, and how to book.

We are an independent business that books licensed technicians, and we are not connected with Hisense. Our booking area covers VIC, NSW, QLD, WA, SA and the ACT.

What is a Hisense aircon gas top up?

Your split system moves heat using refrigerant, often called gas, which circulates through copper pipes between the indoor and outdoor units. The compressor pumps it around, and it changes between liquid and vapour as it absorbs and releases heat. Because the loop is sealed, the amount inside should stay the same for the life of the unit.

A top up means adding refrigerant to bring the charge back to the level the manufacturer specifies. Each model has its own correct charge, which is listed on the rating plate along with the refrigerant type. So a technician cannot simply guess, and adding the wrong amount causes its own problems.

Why a top up alone is rarely the answer

If gas has gone, it went somewhere. Refilling without fixing the leak means the level drops again, sometimes within weeks and sometimes over a season. Meanwhile, the escaping refrigerant harms the environment and the system runs inefficiently. In short, a responsible technician will look for the leak before recharging.

Signs your split system may be low on refrigerant

Low gas has a fairly distinctive pattern, although several other faults can look similar. Consider these clues together rather than on their own.

• Cool mode blows air that is only slightly cooler than the room
• Heat mode produces weak warmth even after the warm up period
• Frost or ice forming on the small pipe at the outdoor unit or on the indoor coil
• The unit runs for long periods without reaching the set temperature
• A hissing or bubbling sound near the pipework
• Oily marks on pipe joints or flare connections
• A code such as EC on models that use it for refrigerant leak or low refrigerant protection

Code meanings vary between Hisense model ranges, so confirm any code against the manual for your model number. Our separate guide on low gas signs covers the symptoms in more depth.

Checks to do before booking a regas

Several everyday issues mimic low refrigerant. Ruling them out first may save you a visit. All of these are safe for owners, provided you never open the unit.

1. Confirm the remote is set to cool or heat, not fan or dry, and that the set temperature makes sense.
2. Take out the filters and wash them if they look dusty, then let them dry fully before refitting.
3. Check the outdoor unit for leaves, covers, storage boxes or plants blocking airflow.
4. Switch off at the isolator or breaker, wait a few minutes, and restart to clear any temporary protection.
5. In heat mode, give the unit a few minutes to warm up and allow for defrost pauses on cold mornings.
6. Write down any code and the model number from the rating sticker on the side of the indoor unit.

If performance is still poor after these checks, the refrigerant circuit is a likely suspect. At that point, a licensed technician needs to take over.

Why only licensed technicians can handle refrigerant

In Australia, working with refrigerant is regulated. Technicians must hold a refrigerant handling licence, and businesses that buy and store refrigerant need the appropriate authorisation. The rules exist because refrigerants can harm the environment and some types are mildly flammable.

Never try to add gas yourself, loosen a pipe nut or use a recharge kit sold online. Refrigerant under pressure can cause frostbite and eye injuries, some types are flammable, and doing this without a licence is against Australian rules.

When you book through us, the job goes to a technician with the right licence for refrigerant work. Ask to see their licence details if you would like reassurance.

How leak detection and repair work

Finding a leak is often the hardest part of the job. Some leaks are obvious, while others are pinholes buried in a coil or hidden inside a wall cavity. So technicians use a mix of methods to track them down.

Common detection methods

• A visual check for oily residue on joints, valves and coils
• Electronic leak detectors that sense refrigerant in the air
• Bubble solution brushed onto suspect joints
• Pressure testing the circuit with dry nitrogen and watching for a drop

Where leaks usually appear

Flare connections at the indoor and outdoor units are a frequent culprit, especially on older installs or after the unit has been moved. Vibration over time can loosen them. In addition, coils can develop tiny holes from corrosion, which is more common in coastal homes exposed to salt air.

Service valves, damaged pipe insulation that lets pipes rub, and joints inside long cable runs are other spots to check. Once the leak is found, the technician repairs or replaces the faulty section.

The recharge process after a leak repair

Recharging properly follows a set routine. Skipping steps is what leads to repeat callbacks.

1. Recover any remaining refrigerant into an approved cylinder where required.
2. Repair the leak point and replace any damaged fittings.
3. Pressure test the circuit to confirm it now holds.
4. Pull a deep vacuum to remove air and moisture from the pipework.
5. Charge the system with the correct refrigerant type by weight, following the rating plate.
6. Run the unit in cooling and heating and check pressures and temperatures.

Moisture is the hidden enemy here. If it stays in the circuit, it can mix with refrigerant oil and cause damage over time. That is why the vacuum stage matters so much.

What happens when the charge is wrong?

An undercharged system struggles in obvious ways. The compressor runs longer, the coil may ice over, and the unit can overheat itself trying to keep up. Over time, that extra strain shortens the life of the compressor.

Overcharging is less obvious but just as harmful. Too much refrigerant raises pressures, increases power draw and can send liquid back to the compressor. As a result, guessing at a top up with a gauge alone is risky. Charging by weight to the figure on the rating plate is the reliable method.

Some Hisense units protect themselves when pressures or temperatures go outside safe limits. For instance, a high discharge temperature is commonly linked to code 13 on many Hisense split systems, and low refrigerant is one possible cause. Check your manual, because codes differ by model.

Leak repairs on ducted and multi split systems

Ducted systems hold more refrigerant and often have longer pipe runs through roof spaces and walls. Consequently, there are more joints where a leak might start, and access can take longer. The same rules still apply, with the leak found and repaired before any recharge.

Multi split systems link several indoor heads to one outdoor unit. A leak at any head or along any run affects the whole system. So the technician may need to test each circuit separately to pinpoint the problem.

Reducing the chance of future leaks

Some leaks simply come with age and cannot be prevented. Even so, a few habits help the system stay sealed for longer.

• Keep the outdoor unit clear and rinse salt or grime off in coastal areas
• Avoid knocking or bending exposed pipework near the outdoor unit
• Replace pipe insulation that has perished in the sun
• Book regular servicing so a technician can spot oily joints early
• Use a licensed installer if the unit is ever moved

Is a gas top up worth it on an older Hisense aircon?

For a newer unit with a single accessible leak, repair and recharge is usually sensible. For an older system with a corroded coil or multiple leaks, the sums can change. The technician can explain what they found so you can weigh up repair against replacement.

Some points to think about include the age of the unit, how well it has performed until now, and whether parts are still easy to get. Also consider energy use, since a newer system may run more efficiently. Either way, the decision is yours once you have the facts.

Gas leaks and the Australian climate

Hot summers across Queensland, Western Australia and inland New South Wales push split systems hard. When refrigerant runs low, cooling falls away just when you need it. Therefore many leaks get noticed in the first proper heatwave of the season.

Cold climates show the problem differently. In Canberra or regional Victoria, a short charge often appears as weak heating on frosty mornings. Coastal suburbs, meanwhile, see more corrosion on outdoor coils, which raises the chance of pinhole leaks.

Warranty and refrigerant faults

Refrigerant leaks on a newer system can fall within the manufacturer warranty. Hisense states a five year parts and labour warranty on split systems sold in Australia, so check your warranty card for details. If you think your unit is covered, contact Hisense before booking an outside repair, since unauthorised work could affect a claim.

Booking a leak repair and regas

Call 03 7048 4120 and describe what the unit is doing. We will arrange a licensed technician to inspect the refrigerant circuit and explain the findings.

Before the call, gather the model number from the rating sticker, note any code, and think about when the problem started. It also helps to mention whether the unit was recently moved, installed or serviced.

The key points on a Hisense aircon gas top up

Refrigerant should never need routine refilling, so low gas almost always means a leak. Rule out dirty filters, wrong settings and a blocked outdoor unit first. After that, leave the job to a licensed technician who will find and fix the leak, vacuum the system and recharge it correctly.

If your Hisense split system has lost its cooling or heating power, call 03 7048 4120 to book a licensed refrigeration technician.