Coastal condo not cold: evaporator grime, not a gas leak
The unit blew air but never cooled. A previous company called it a gas leak and recommended a new coil. Not cold does not always mean low gas. Coastal humidity can cake a coil so thickly that cooling stops.
By Team Snowflake | Reviewed 11 Mar 2026
Case summary
Daikin Wall-mounted8 years oldCondoMarine Parade, Singapore
- Concern
- Previous advice was that salt air had corroded the coil, so it needed replacing along with a full gas recharge
- Found
- Evaporator coil heavily caked with grime from years of coastal humidity, 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 previous company blamed a gas leak from salt-air corrosion on the evaporator coil, and quoted for a new coil and a full gas recharge. 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 of coastal humidity had built a thick, sticky grime over the evaporator coil fins. Salt-laden air leaves a residue that bonds to aluminium fins harder than ordinary dust, and each layer builds a dense coat a routine wash cannot reach. 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.
- Near the coast, salt air bonds 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.
Related reading
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