How do I know if there's a leak or if the gas was just low to begin with?

Refrigerant doesn't deplete on its own — it's a closed system. If your unit needs topping up repeatedly, gas is escaping somewhere. A pressure test confirms whether there's an active leak, and a connection check finds where.

If the leak is fixed, will I need to top up again?

No. Once the joint is sealed and pressure-tested, the system holds its refrigerant. The customer in this case hasn't needed a top-up since. Sealing the source stops the cycle.

Can I just keep topping up instead of fixing the leak?

You can, but the leak is still there. Every top-up is temporary — the gas escapes again through the same gap. Fixing the source once is the only way to stop paying repeatedly.

Repeated gas loss traced to slow leak at flare joint

Aircon case in Clementi, Singapore: cooling loss traced to slow refrigerant leak at indoor flare joint after targeted diagnosis checks.

Case details

What client reported

I've topped up the gas twice in about four months. Each time it works for a few weeks, then the cooling starts to fade. My previous technician just keeps doing the top-up without checking further.

ProblemCooling loss

UnitDaikin · Wall-mounted · 8 years old

LocationHDB · Clementi, Singapore

What we found

The unit was blowing warm air when we arrived. Pressure was well below normal — consistent with the history. Low gas was confirmed, but that only describes the symptom, not the cause.

Refrigerant pressure well below operating range — confirmed low gas
Applied nitrogen charge and sealed the system for an overnight hold test
Pressure had dropped measurably by the next morning — active leak confirmed
Leak traced to the indoor flare joint using bubble solution — small gap at the connection

The flare joint at the indoor unit connection had a slight gap — enough for refrigerant to escape slowly. Not fast enough to notice in a day, but fast enough to empty the system over a few weeks. Every top-up restored cooling temporarily, but the leak was never sealed.

What we did

Fixable, not a replacement. We tightened and re-sealed the flare joint, pressure-tested it overnight again to confirm the hold, then recharged the system. The unit should now hold its gas indefinitely.

The joint was sealed and the system recharged. Cooling has been stable since the repair — no further top-ups have been needed.

Timeline

Day 1

Unit blowing warm air — fourth top-up in under a year requested

Day 2

Nitrogen pressure test held overnight to confirm pressure drop

Day 2

Overnight pressure test confirmed active leak at flare joint — sealed and recharged

What we learned

Top-up and hold vs. top-up and repeat.

Top-up that holds for years = the leak was minor and has since sealed, or the original charge was just low
Top-up, cold for weeks, fades again = active leak still present
A pressure test is the only way to confirm whether gas is escaping — guessing wastes money

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