How much will it cost to keep topping up the gas?

If you keep topping up without fixing the leak, you'll be paying repeatedly. The customer in this case had spent on two top-ups before finding the leak. Fixing the source once stops the cycle completely.

Will this problem happen again after you fix it?

No. Once we seal the connection and pressure-test it, the system holds its refrigerant indefinitely. This customer hasn't needed a top-up since the repair was done.

Can I just keep topping up instead of fixing it?

You could, but each top-up is temporary relief. The leak is still there, draining the gas. Finding and fixing the source is the only way to stop the problem for good.

Cooling loss traced to refrigerant leak, not just low gas

Aircon case in Tampines, Singapore: cooling loss traced to slow refrigerant leak at pipe connection after targeted diagnosis checks.

Case details

What client reported

I've topped up the gas twice in six months. Each time it's cold for a few weeks, then it slowly gets warm again. I don't know if something else is going on.

ProblemCooling loss

UnitMitsubishi Electric · Wall-mounted · 5 years old

LocationHDB · Tampines, Singapore

What we found

The unit was blowing warm air and refrigerant pressure was well below normal. Low gas was confirmed, but low gas is a symptom — we needed to find where it was going.

Refrigerant pressure well below normal range
Nitrogen pressure test applied — system pressurised and gauges left overnight
Pressure dropped by next morning, confirming an active leak
Leak located at indoor-side pipe connection using bubble solution

The pipe connection had a small gap — likely from a loose seal. Refrigerant was escaping slowly through it. Not fast enough to notice in a day, but fast enough to drain the system over a few weeks. Each top-up restored cooling, but the leak kept letting the gas out again.

What we did

Fixable problem. We repaired the loose connection, pressure-tested it to confirm the seal holds, then recharged the system. After that, it should hold its refrigerant indefinitely.

The connection was repaired and the system recharged. Cooling has been stable since, with no further top-ups needed.

Timeline

Day 1

Unit blowing warm air—multiple gas top-ups in six months

Day 2

Nitrogen pressure test left overnight to confirm pressure drop

Day 2

Pressure test left overnight confirmed slow leak at pipe connection

What we learned

How to tell if it's low gas vs. a leak.

One-time top-up that holds for years = the charge was likely low from installation or a very minor past leak
Repeated top-ups every few weeks/months = active leak
Testing confirms where the gas is going, so you don't waste money on guessing

Common questions

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