Annual aircon service in Pakenham — what’s on the checklist.

Here is exactly what we do on an annual service. Whether the unit is a 2.5 kW Daikin Cora in a Cardinia Lakes bedroom or a 14 kW Mitsubishi Heavy Industries ducted reverse-cycle in Heritage Springs, the principle is the same: measure everything, clean everything that’s dirty, and tell you the honest truth about whether the system is healthy.

1. Filter wash & inspect — return-air and indoor head filters pulled, washed, dried, refitted. Replace if perished.
2. Indoor coil chemical clean — antibacterial foaming cleaner on the evaporator fins, rinsed clear. Removes the biofilm that causes the musty smell on first start each season.
3. Indoor fan barrel clean — the cross-flow fan loads up with dust which kills airflow and unbalances the rotor (causing vibration). Brushed and vacuumed.
4. Condensate drain flush — the #1 cause of summer leaks dripping onto ceilings in Cardinia Lakes. We flush with anti-algae solution and verify free flow.
5. Outdoor coil wash — high-pressure rinse of the condenser fins. On rural-edge Pakenham sites this is where most of the year’s efficiency loss lives.
6. Fin straightening — combed back where bent (whipper-snipper damage, kids’ cricket balls, the usual).
7. Refrigerant pressure check — high-side and low-side gauges attached. Readings logged. Compared against manufacturer spec at measured ambient.
8. Superheat & subcooling — calculated from the gauges and temperature probes. Tells us if the charge is correct, undercharged, or overcharged.
9. Electrical check — supply voltage, compressor running amps, capacitor microfarad value, terminal tightness, contactor pitting.
10. Isolator & CES check — confirms the outdoor isolator works and is correctly fused, per AS/NZS 3000.
11. Function test — full cycle on cooling and heating, target temperature reached within manufacturer time, no error codes, no abnormal noise.
12. Written report — one-page sheet with every reading, a green/amber/red status, and any recommended repairs with fixed prices.

Why some Pakenham sites get a 6-month rotation.

Pakenham itself is mostly safely inland — about 35 km from Western Port — so coastal-salt corrosion is not usually the driver. But two situations push us to recommend a 6-month service rotation instead of an annual one. The first is properties on the southern rural-residential fringe of Cardinia Shire that occasionally catch salt-laden summer wind off the bay; we see aluminium-fin corrosion on those condensers inside two summers. The second is rural-edge Cardinia properties next to crop fields, pine plantations or the Bunyip State Forest — pollen and seed loading clogs an outdoor coil twice as fast as a normal suburban site. On those sites we do a winter service (May/June) before the heating runs hard and a spring service (October) before cooling season — same 12-point checklist, half the duration between visits.

What the gauge readings actually mean.

The refrigerant gauges are the most honest diagnostic tool we carry. On an R32 split system running steady-state at 30°C ambient, the high-side should sit at 2.6–3.2 MPa and the low-side at 0.7–0.9 MPa. If the high-side is 1.8 MPa, the system is significantly undercharged — that means a leak, not normal wear. The subcooling reading (high-side liquid temperature compared to saturation) tells us how far below charge we are; the superheat (low-side suction temperature compared to saturation) tells us where the leak is likely to be hiding. A high-superheat / low-subcooling combination on a Pakenham split that “just isn’t cooling like it used to” almost always means a slow flare leak that’s been losing 5–10 grams of R32 a month for two years.

When the service becomes a re-gas job.

If the gauges say the system is undercharged, an honest service doesn’t just top it up and walk away. Topping up without finding the leak is illegal under the Ozone Protection and Synthetic Greenhouse Gas Management Regulations (ARC-licensed technicians can lose their RHL for it) and it wastes your money — the gas will be gone in 12–24 months. The honest call is: pressure-hold test, UV-dye injection or electronic-sniffer leak detection, repair the leak (usually a flare re-do or a corroded brazed joint), evacuate the system, and recharge to manufacturer spec. We quote that as a separate job with a fixed price before doing it — see our refrigerant leak detection page for the full process.

2026 service pricing — Pakenham.

Single-head split: $180–$240. Multi-head (first head $180, each additional $80). Ducted reverse-cycle 12–16 kW: $290–$380. Evaporative cooler pre-summer service: $220–$280. Combined ducted gas heater + split-system house package: $420–$520. All prices include the full 12-point checklist and written report. No fuel levy, no after-hours surcharge for booked appointments.