Carbon monoxide testing on ducted heaters: why every 2 years matters
Carbon monoxide is the gas-safety risk that doesn't announce itself. It's colourless, odourless, slightly lighter than air — and at concentrations as low as 70 parts per million it can put a healthy adult to sleep. Most CO incidents in Victorian homes trace back to one source: an ageing ducted gas heater with a cracked or blocked heat exchanger.
Why CO testing matters
Modern ducted gas heaters route combustion gases through a flue to the outside. The heat exchanger separates those flue gases from the air flowing into your house. When the exchanger develops a hairline crack (corrosion, thermal stress, age) or when the flue blocks (bird nest, debris), combustion gases bleed back into the supply air. That's how CO ends up in your living room.
Energy Safe Victoria recommends a full CO test every two years on any ducted gas heater older than 5 years. We test on every annual service, regardless of age.
What we test for
- Atmospheric CO in the supply-air stream (measured with a calibrated meter near the diffusers)
- Flue CO at the appliance flue outlet to verify combustion is clean
- Flue draft — pulling air outwards, not stalling
- Heat exchanger integrity via a smoke test or visual inspection
- Gas pressure at the appliance against manufacturer spec
- Return-air dampers and seals for negative pressure leaks
Red flags before you call us
- Yellow or wavy burner flame instead of crisp blue
- Soot marks above the heater outlet or on diffusers
- Persistent unexplained drowsiness or headache when the heater is running
- Pilot light that won't stay lit
- Heater starts and stops more than usual
Any of those? Stop using the heater and ring us — or any licensed gas fitter. Same-day callout if the symptoms are active.
Our service rate
Flat $280 + GST for an annual gas heater service across SE Melbourne (or $250 + GST for members). Includes the full CO test, written report with photos, gas pressure check and combustion analysis — everything an insurance assessor or property manager will ask for.
FAQ
Does my landlord need to organise this?
Yes. Under Victorian rental law, gas appliances must be safety-checked every 2 years by a licensed gas fitter. We provide a written compliance record for the rental file.
What if you find a CO leak?
We isolate the appliance immediately, write up the fault, and quote either repair or replacement. We'll never sign off a working heater that's leaking CO.
Do CO alarms make this unnecessary?
No. CO alarms warn you when concentrations are already dangerous. Annual servicing prevents leaks in the first place. Both layers, please — alarms cost $40 at Bunnings.