Coastal condo not cold: evaporator grime, not a gas leak

The unit blew air but never cooled, and a leaked refrigerant charge looked like the obvious answer. Not cold does not always mean low gas. Coastal humidity can cake an indoor coil so thickly that cooling stops altogether.

By Team Snowflake | Updated 28 Jul 2026

Case summary

Daikin Wall-mounted8 years oldCondoMarine Parade, Singapore

Concern: An eight-year-old unit blowing warm air pointed to a corroded coil and lost gas, which meant a replacement coil and a recharge.
Found: Evaporator coil heavily caked with years of ordinary indoor humidity, dust, and cooking aerosol, blocking heat exchange despite normal gas levels
Key check: Inspected evaporator coil condition and checked gas readings before recommending any gas or coil work
Result: Full cooling returned after the chemical servicing. The unit ran a complete cycle and held the set temperature in the master bedroom. No coil replacement, no gas recharge, and the unit stayed in service.

What we were told

The master bedroom unit blew air but stayed warm. A new coil and a full gas recharge had already been priced up. That felt like a lot for a unit that still ran. The unit is eight years old, so the owner asked whether to repair or replace.

What we checked

Before assuming the gas had leaked, we inspected the evaporator coil and measured gas readings at the outdoor unit service port. These two checks separate the causes fast. A dirty coil blocks heat transfer while readings stay normal. A leak drops the gas reading and can ice up the copper pipes.

The evaporator coil was caked with a thick, sticky layer of grime. Almost no bare fin was visible even under a torch.
Air passed through the unit, but the grime kept it from reaching the cold fins underneath.
Gas readings at the outdoor unit were normal for this Daikin model. Suction and discharge were stable, so the charge was intact.
No frost or ice formed on the coil or copper pipe, which ruled out a low-gas fault.
After chemical servicing dissolved the grime, the fins were exposed again and a clear temperature drop showed at the supply grille.

What we found

Eight years without a deep clean had let ordinary indoor humidity, dust, and cooking aerosol drifting in from the kitchen bond onto the evaporator coil fins. Layer by layer, almost no bare fin was left. That coat insulated the fins from the passing air, blocking heat transfer between the cold refrigerant and the warm room. The charge was full and the compressor ran normally, but no heat could cross the coil, so the unit blew room-temperature air. The cause was grime, not lost gas.

What fixed it

The coil did not need replacing and there was no gas leak. Chemical servicing with an alkaline coil cleaner dissolved the grime and freed the fins for heat transfer. We rinsed the coil, reassembled the unit, and ran a cooling cycle. The gap between intake and outlet air was back in range within minutes. No parts, no gas recharge, no new coil. Given the coastal site, we advised servicing every six to eight months.

Outcome

Full cooling returned after the chemical servicing. The unit ran a complete cycle and held the set temperature in the master bedroom. No coil replacement, no gas recharge, and the unit stayed in service.

What this case teaches us

A caked coil can mimic a gas leak

A grime-blocked coil and a gas leak both blow warm air. Stable gas pressure with no icing points to a dirty coil, not lost refrigerant.
Ordinary indoor humidity, dust, and cooking aerosol can bond a film a routine wash leaves behind. Deeper chemical cleaning may be needed every six to eight months.
Before approving a new coil or a gas recharge, ask whether the coil was checked and the gas measured. A cleaning often costs far less.

Questions this case answers

Aircon blowing but not cold: is the gas leaking?

Not always, and from inside the room the two look the same. Gas readings at the outdoor service port on this Marine Parade unit were normal for the model, with suction and discharge both stable. No frost or ice formed on the coil or the copper pipe either, which is what a genuine low-gas fault tends to show.

Can a dirty coil stop an aircon cooling completely?

It can. Eight years without a deep clean had buried the evaporator fins under a thick, sticky layer, with almost no bare metal visible even under a torch. Air passed through the unit but never reached the cold fins beneath. Heat could not cross the coil, so the unit blew room-temperature air.

Why does grime build up on the indoor coil in the first place?

Indoor humidity, household dust and cooking aerosol drifting in from the kitchen condense onto the cold fins and bond there, layer upon layer. A routine wash leaves that film behind. An alkaline coil cleaner dissolves it and frees the fins, and on a coastal site every six to eight months suits.

Should an eight-year-old unit be repaired or replaced?

Find out what is actually wrong first. Nothing was replaced here: no coil, no gas recharge, no parts at all. Once the grime dissolved and the fins were exposed, a clear temperature drop showed at the supply grille and the master bedroom held its set temperature through a full cycle.

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Tell us what’s going on. Symptoms, setup, photos, anything we should know. We’ll assess and come back with the right next step.

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