The annual service for a Melbourne gas ducted heater is not a discretionary maintenance preference — it is the primary safety check for one of the few household appliances that can produce a life-threatening gas without any obvious warning. Gas Safety Victoria recommends annual professional servicing of all gas ducted heaters. This guide explains exactly what a complete annual service covers, what homeowners can and cannot do themselves, and why the April or May window is the right time to book for Melbourne households.
What an Annual Service Covers
A complete annual service for a Melbourne gas ducted heater is a multi-part inspection and maintenance procedure. The following table summarises what a thorough annual service should include. If a quoted service omits any of the safety items, it is not a complete annual service.
| Service Item | Type | Why It Matters |
|---|---|---|
| Heat exchanger inspection | Safety | Primary CO risk — detect cracks before CO enters air stream |
| Combustion gas test at supply outlets | Safety | Confirms no CO in house air stream during operation |
| Flue integrity check | Safety | Confirms combustion gases are exhausting outside, not spilling inside |
| Gas valve leak test | Safety | No gas leaks at valve or connections |
| Safety limit switch test | Safety | Confirms overtemperature protection is functional |
| Burner inspection and clean | Performance | Correct combustion efficiency; correct air/gas ratio |
| Flame character observation | Performance | Blue flame indicates correct combustion; yellow or orange indicates incomplete combustion |
| Blower motor inspection | Performance | Motor bearings, capacitor, airflow performance |
| Return air filter check | Performance/Safety | Blocked filter overheating heat exchanger fatigue |
| Controller function test | Performance | Correct thermostat response; zone command execution |
| Zone damper response check | Performance | Each zone opens and closes correctly on command |
Safety Checks: Heat Exchanger and CO
Heat exchanger inspection
The heat exchanger is the critical safety component in a gas ducted heater. It keeps combustion gases (including carbon monoxide) physically separated from the house air stream. Over years of thermal cycling — particularly in systems subjected to overheating from blocked filters — small cracks can develop in the heat exchanger metal. A cracked heat exchanger can allow CO to enter the house air stream without affecting heating performance or triggering any visible alarm.
The annual heat exchanger inspection includes: visual inspection through the inspection port for visible cracks, holes, or distortion; combustion gas testing at multiple supply outlets during heater operation to detect CO in the house air stream; and observation of the heat exchanger condition relative to the system’s age. See our carbon monoxide and ducted heating safety guide for more detail.
Flue inspection
The flue pipe carries combustion gases from the heat exchanger to the outside (typically through the roof). A damaged, blocked, or disconnected flue can cause combustion gases to spill into the roof space and potentially into the home. The annual service includes confirming the flue is connected, undamaged, and performing correctly.
Performance Checks: Burner, Blower, Filter
Burner clean and adjust
The gas burner assembly accumulates dust, lint, and carbon deposits over the heating season. An annual clean removes this buildup and restores the correct air/gas mixture at the burner ports. Incorrect combustion produces an orange or yellow flame (incomplete combustion), increased CO production, and reduced efficiency. The burner clean takes 10 to 20 minutes and is a standard part of every annual service.
Blower inspection
The blower motor moves house air through the heater and into the duct system. The annual service inspection includes checking: motor bearing condition (listening for grinding or rumbling indicating wear); blower impeller cleanliness (a dust-coated impeller reduces airflow and efficiency); starting capacitor condition (a degrading capacitor causes slow starting and reduced blower speed); and blower belt condition on older belt-drive systems.
Filter check
The return air filter is inspected and, if needed, replaced during the annual service. If the homeowner has been performing monthly DIY filter checks through the season, the filter is typically in good condition at the April or May service. If the filter has not been checked since the previous service, it is likely to need replacing. Replacement is included in the combined service + filter price of $350 to $500.
Zone System Checks
For Melbourne homes with zone control, each zone’s damper actuator is exercised through open and close commands during the service to confirm correct operation. Zone actuator failure is common in systems over ten years old — the annual service is the appropriate time to identify and quote for actuator replacements before the season starts, rather than during the season when a stuck zone causes heating disruption.
The controller is also tested for zone scheduling accuracy — confirming that programmed schedules execute correctly and that temperature setpoints respond as expected. Battery-powered wireless controllers are tested with fresh batteries if the annual service falls near the end of the battery’s typical service life.
What Homeowners Can and Cannot Do
Homeowner tasks
- Return air filter: inspect and clean or replace monthly during the heating season. See our filter guide. This is the most impactful homeowner maintenance action.
- Circuit breaker check: if the heater is completely non-responsive, check the heater circuit breaker at the switchboard. Reset once if tripped; do not reset again if it trips immediately.
- Controller fuse: if the wall controller shows no display, check the controller’s internal fuse (3A or 5A blade fuse inside the controller face plate).
- Controller batteries: for wireless controllers, replace batteries annually.
Professional-only tasks
- Gas valve inspection and replacement — requires gas licence
- Heat exchanger inspection and combustion gas testing — requires calibrated equipment
- Burner cleaning and adjustment — requires gas licence and combustion knowledge
- Flue inspection and repair — requires roof space access and gas licence
- Blower motor or capacitor replacement — electrical safety issue in roof space
- Zone actuator or controller board replacement — low-voltage wiring in roof space