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Carbon Monoxide Testing Melbourne
The Hazard You Cannot Smell, The Test That Catches It
Carbon monoxide is colourless, odourless and produced by every gas appliance that burns fuel for heat. In a healthy installation the combustion products leave the building through a flue. In a faulty installation, blocked flue, cracked heat exchanger or negative pressure environment, those products can spill back into living space at concentrations that make occupants drowsy, sick or worse before anyone notices a smell or a flame change.
A carbon monoxide test is the procedure that picks up that spillage before the occupants do. It is run with a calibrated flue gas analyser at the appliance, at the flue, and in the room where the appliance lives. The reading either confirms the appliance is burning cleanly and venting properly, or flags a fault that needs a fix before the appliance is left in service.
Gaslec runs carbon monoxide testing as a discrete line item because it answers a different question from a general gas safety check. A safety check asks “is this installation compliant.” A CO test asks “is this appliance, right now, producing or spilling carbon monoxide at a level that puts occupants at risk.” The two services overlap, but the CO test is the one that produces the ppm reading.
Where Carbon Monoxide Problems Actually Come From
Most carbon monoxide incidents in Victorian homes trace back to one of four causes. First, open-flued gas heaters running in rooms that have been retrofitted with high-extraction rangehoods, bathroom exhaust fans or sealed building envelopes. The fans pull air out of the room faster than the flue can pull combustion products up, the flue reverses, and the appliance vents into the room instead of out of the roof.
Second, cracked or corroded heat exchangers on older gas heaters. When the metal separating the combustion chamber from the airflow path develops a crack, flue gas including carbon monoxide gets mixed into the warm air the appliance is blowing into the room. The appliance still appears to work normally and the flame still looks correct.
Third, blocked or damaged flues. Bird nests, leaf litter, structural movement that has fractured a flue joint, or insulation that has been packed against a flue and reduced its draw. The appliance fires, but the combustion products do not leave the building cleanly.
Fourth, appliances installed in spaces they were never rated for. A heater designed for a ventilated space installed in a sealed cupboard. A water heater designed for outdoor mounting installed indoors. The appliance burns clean in isolation but spills carbon monoxide because the surrounding installation does not give it the airflow it needs.
A carbon monoxide test detects all four causes from the same physical evidence: ppm readings at the appliance and in the room, flue draw measurements, and a negative pressure test that simulates worst-case extraction conditions.
When To Test, & How Often
Three triggers usually drive a carbon monoxide test on a property.
The first is symptom-driven. Occupants reporting headaches, drowsiness, flu-like symptoms or unexplained tiredness that improves when they leave the property. These reports get a CO test before the next sleep cycle in the property, not on the next available appointment.
The second is appliance-driven. Any open-flued gas heater more than ten years old. Any appliance that has been moved, modified, or had its flue altered. Any installation where new exhaust fans, rangehoods or building works have changed the airflow in the room since the appliance was last tested. Any appliance that has tripped, shut down on safety, or produced an unusual flame or noise.
The third is portfolio-driven. Rental providers, property managers, owners corporations and commercial operators who include CO testing in the annual gas safety check cycle so every appliance is tested at least once a year regardless of symptoms or appliance changes. This is the lowest-cost way to catch a slow-developing fault on a heat exchanger or flue before it becomes an incident.
For investors and managers with multiple properties, Gaslec schedules CO testing alongside the annual gas safety check so the appliance is tested on the same visit the rest of the gas work is signed off on.
What Happens On The Day
A carbon monoxide test is a methodical, instrument-based check. It is not a sniff test, it is not a flame look, and it does not finish with the technician saying “looks fine.” Every result is a number on a calibrated analyser.
The technician arrives with a flue gas analyser inside its calibration window, a manometer for flue draw and room pressure, an ambient CO meter for the occupied space, and the manufacturer’s service data for the specific appliance being tested. The appliance is run from cold start through to steady-state burn while readings are taken at the burner, at the flue outlet, and in the room.
Where the appliance is open-flued, the technician runs a negative pressure test. Every exhaust fan, rangehood and clothes dryer in the building is turned on simultaneously to simulate the worst-case extraction load. The room pressure and the flue draw are measured under that load. If the flue reverses or the draw falls below the manufacturer’s spillage threshold, the appliance fails the test even if the steady-state burn was clean.
Ambient CO is logged in the room over the course of the test. Any reading above the agreed action threshold is treated as a fail.
At the end of the visit, the result is recorded on a CO test certificate with the appliance details, the readings, the test conditions, the pass or fail decision, and any required remedial work. The certificate is uploaded to the Gaslec portal the same day. Where the appliance fails, the technician will discuss the options before leaving: repair, restrict use, or condemn pending replacement.
Who We Look After
Gaslec runs gas safety checks for property managers, owners and facility teams across Melbourne, from a single residential rental on a quiet street to a portfolio that crosses six industries on the same calendar. The conversation looks the same whether it’s for one property or a hundred. One point of contact, one portal, one supplier, one team.
Where Carbon Monoxide Testing Is Heading
Three shifts are worth noting for any property owner or manager planning ahead.
First, building envelopes are getting tighter. Modern weather sealing, double glazing and insulation reduce the natural air change in a room, which makes open-flued appliances more prone to flue reversal under extraction load. The same appliance that tested clean in a draughty 1970s house can fail the same test after a recent retrofit, even if the appliance itself has not changed. CO testing matters more in a tighter building, not less.
Second, the ppm reading is becoming the evidence of choice. Tenant complaints, owners corporation disputes and insurance claims that touch on combustion safety increasingly turn on whether a CO test has been done and what the reading was. A dated certificate with a clean ppm reading is the kind of evidence that ends those conversations early.
Third, scheduled testing is replacing reactive testing. The pattern of “we will test if someone gets sick” is being replaced by annual testing across managed portfolios, the same way smoke alarms moved from optional to expected. Rental providers and owners corporations adding CO testing to the annual cycle now will have a multi-year clean record by the time the change formalises further.
Why Gaslec For Carbon Monoxide Testing
Gaslec runs gas, plumbing, electrical and smoke across the same business, so a CO test can be booked alongside the annual gas safety check, electrical safety check and smoke alarm safety check in a single property visit. One booking, one site attendance, one consolidated set of certificates.
The technicians running CO tests are licensed gas fitters with the appliance-specific training to interpret the flue gas analyser readings against manufacturer service data. The analysers and manometers carried on the van are inside their calibration windows and the calibration dates are recorded on every certificate.
Every CO test certificate is uploaded to the Gaslec portal. Agents and owners corporation managers with multiple properties can see the test status of every appliance from one screen, which makes annual audits and end-of-tenancy reporting faster than chasing individual PDFs.
Gaslec services Melbourne and the surrounding suburbs.
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