Ducted Heating Not Working — Melbourne Fault Guide

A Melbourne ducted heater that stops working on a cold May morning is one of the most disruptive home appliance failures — affecting every room in the house simultaneously. The majority of “no heat” faults have a limited set of causes, and most follow a recognisable pattern that allows systematic diagnosis. This guide works through each fault category in order of likelihood, with clear checks for what Melbourne homeowners can safely attempt and when to call a technician.

System Runs But No Heat

If the blower is running and air is coming from the ceiling outlets but it is not warm, the burner is not igniting while the blower operates. Work through these checks:

1. Confirm the controller is set to heating mode

Some Melbourne ducted heating controllers have a “fan only” mode where the blower circulates air without calling for heat. Check the controller is set to “Heating” and the set temperature is above the current room temperature. On Brivis and Rinnai controllers, the mode indicator should show a flame or heating symbol, not a fan symbol.

2. Check the gas supply

Confirm the gas supply is on — check if other gas appliances (hot water, cooktop) are working. If no gas appliances are working, contact your gas supplier. If other appliances work but the heater does not, the issue is at the heater itself.

3. Look for an error code

Modern Brivis and Rinnai controllers display an error code when ignition fails. Note the code and refer to the error codes section below for the fault category. If no code is displayed but the blower runs without heat, the gas valve or ignition system is the likely fault.

Heater Won’t Start at All

Check the circuit breaker

Go to the main switchboard and locate the circuit breaker for the heater. It may be labelled “Ducted Heating”, “Heater”, “Gas Heater”, or “Furnace”. Reset it once by pushing it fully to the off position and then back to on. If it trips immediately again — do not reset a second time. This indicates a short circuit or earth fault requiring a technician.

Check the controller fuse

If the circuit breaker is not tripped but the wall controller shows no display, the controller’s internal fuse may have blown. On Brivis and Rinnai controllers, a 3A or 5A blade fuse is usually located inside the controller. Remove the controller face plate (typically two screws) and inspect the fuse — a blown fuse is visually obvious (broken wire inside). Replace with the same rating fuse and test.

Check the thermostat batteries

If your Melbourne ducted heater uses a wireless battery-powered thermostat or remote controller (common in Rinnai and some Brivis systems), low batteries can cause complete controller failure. Replace the batteries before calling for service.

Ignition Failure — No Flame

Ignition faults account for the majority of “no heat” service calls in Melbourne each winter. The ignition sequence on a modern gas ducted heater is: call for heat   gas valve opens   spark igniter fires   flame sensor confirms flame   heater runs. Failure at any step in this sequence produces a lockout.

Flame sensor fouling

The most common cause of ignition lockout in Melbourne ducted heaters is flame sensor fouling. The flame sensor — a small metal rod that detects the presence of a flame by measuring flame rectification current — accumulates carbon deposits during the heating season. As deposits build up, the measured current drops below the controller’s threshold and the controller concludes there is no flame and shuts the gas valve. The fix is flame sensor cleaning or replacement: $280 to $380 as a complete job.

Ignition PCB failure

If the spark igniter does not fire at all (no clicking sound from the roof space when the heater is called), the ignition PCB or the spark module may have failed. PCB replacement is $320 to $480 as a complete job. Wiring connections at the PCB should also be checked — loose connectors are occasionally the cause and are inexpensive to rectify.

Blower Fan Fault

The blower motor draws return air from the home into the heater body and pushes warmed air into the supply duct system. Blower faults produce no airflow or severely reduced airflow from ceiling outlets.

Blower capacitor failure

The blower motor’s starting capacitor is an electrolytic component that wears over time. When it fails, the motor may hum without turning, start slowly, or fail to start at all. Capacitor replacement is $280 to $380 as a complete job. This is not a homeowner DIY task — capacitors store a charge that must be discharged safely before handling.

Blower motor bearing seizure

Older blower motors in Melbourne ducted heaters that have not been regularly lubricated (part of the annual service) can develop bearing wear. Signs include a grinding or rumbling sound from the roof space and reduced airflow over time. Motor replacement is $450 to $750 as a complete job.

Zone Not Heating

If the main heater is running but a specific zone is not receiving heated air, the fault is typically in the zone system rather than the heater itself.

Zone damper actuator failure

Motorised zone damper actuators (the motors that open and close the damper plates in the duct runs) are the most common cause of zone faults. Symptoms: one zone always off regardless of controller setting, or one zone always on regardless of setting. Actuator replacement is $280 to $420 per zone as a complete job.

Zone controller board fault

If multiple zones behave incorrectly or the zone controller display is erratic, the central zone controller board may have failed. Replacement is $350 to $600. Note the error codes or behaviour patterns to describe to the technician — this allows them to bring the correct replacement board.

Error Codes and Lockout Reset

Resetting a lockout

Most Brivis and Rinnai ducted heaters allow a manual lockout reset by turning the controller off, waiting 60 seconds, and turning it back on. This resets the ignition lockout counter and allows another ignition attempt. If the heater runs after a reset but the fault recurs, the underlying fault is still present and will trigger lockout again. Repeated resets mask a developing fault — book a service if the heater requires more than one reset per season.

Common Melbourne ducted heater error codes

For a complete fault diagnosis, call FreshDuct on 0431 918 137 — describe the error code and the symptom pattern and we can often diagnose the likely fault before attending.

Frequently Asked Questions