Case Study: 4-Unit Office Chemical Overhaul in Jurong West

The call

A small accounting office on the third floor of a Jurong West Avenue 1 commercial block called us on a Friday afternoon. Their four wall-mounted fan coils — installed eight years ago, never chemically washed — were running from 8am to 10pm but the thermostat reading was stubbornly stuck at 27°C with the setpoint at 23°C.

A previous contractor had quoted them S$3,500 to replace all four units with new Daikin 12,000 BTU systems. The tenant called us for a second opinion before signing.

The diagnosis (1 hour, S$80 waived on proceed)

We sent two technicians on the Saturday morning. Standard diagnosis routine:

1. Pressure test on each system — three out of four had pressures within spec. The fourth was 18% below.
2. Visual inspection of coils — every fan coil had heavy biofilm buildup on the evaporator fins. Two had mould visible at the louvre.
3. Drain pipe flush test — three of four drains were partially blocked, slowing the drainage and reducing thermal exchange efficiency.
4. Capacitor reading on outdoor units — Unit 4’s start capacitor was reading 22µF on a 35µF spec — failing.

The verdict: this wasn’t a system end-of-life situation. Three units needed a deep chemical overhaul to restore the heat exchange efficiency that years of biofilm had stolen. The fourth needed an aircon repair — a capacitor replacement and a gas top-up.

The work (full Saturday, S$680 total)

We laid dust sheets across the entire office floor. Computer towers were covered with plastic. Removed our shoes at the entry — standard practice even for commercial calls.

For each of the three units that needed an overhaul:

• Disconnected power at the breaker
• Removed the front cover, filter, and louvre
• Carefully dismantled the fan coil from its mounting bracket
• Carried it (two-person lift) to a tarpaulin-covered area
• Separated the blower from the casing
• Soaked the coil in approved chemical solution (45 minutes)
• Brushed and rinsed the blower
• Pressure-flushed the drain pipe end-to-end
• Reassembled, refitted, and reconnected

For Unit 4: removed the front panel of the outdoor condenser, drained any remaining R32, replaced the failing start capacitor, vacuumed the system to 500 microns, and recharged with the correct R32 weight.

The result (measured at the supply outlet)

Before:

• Average supply temperature: 19°C with setpoint at 23°C
• Compressor running ~92% of the time
• Slow cooling — thermostat reading stuck at 27°C after 4 hours

After:

• Average supply temperature: 12°C with setpoint at 23°C
• Compressor running ~64% of the time
• Office reached 23°C within 45 minutes of switch-on

What it cost

Item	Cost
Chemical overhaul × 3 fan coils	S$160 × 3 = S$480
Capacitor replacement (Unit 4)	S$120
R32 top-up (Unit 4, ~150g)	S$80
Total	S$680

Compared to the S$3,500 replacement quote the previous contractor had given, the tenant saved S$2,820 — and the units now have an estimated 4–6 more years of useful life before replacement is genuinely needed.

The lesson

If your aircon isn’t cooling properly, replacement is rarely the right first answer. A proper diagnosis on the unit, the gas, and the drain almost always reveals a fixable issue — at a fraction of the cost.

Three rules that come from this case:

1. Always pressure-test before assuming a system is dead. Pressures within spec mean the refrigerant circuit is still sealed.
2. Biofilm buildup is invisible from the front. A unit can look clean and still be 30%+ inefficient at the heat exchanger.
3. A failing capacitor mimics low-gas symptoms. Don’t replace the system before testing the cheapest part to fix.

When to call us

If your aircon has been running but underperforming for more than two weeks, get a diagnosis before you accept a replacement quote. We diagnose for S$80 (waived if you proceed with the work), and the diagnosis itself takes around 30 minutes per unit.

WhatsApp +65 9182 5233 with the unit count, postal code, and a brief description. We’ll quote a slot within the hour during business hours.