If you’ve turned your gas ducted heater on and nothing happens — no ignition, no airflow, no heat — you’re not alone. It’s one of the most common calls we receive at the start of winter in Melbourne.

The good news is there are a handful of causes that account for the vast majority of cases. Some you can check yourself in a couple of minutes. Others need a licensed gas tech.

Here’s a logical walkthrough — start at the top and work down.

⚡ Check the Power Supply First

Before assuming a fault, confirm the basics:

• Is the heater switched on at the wall?
• Has the circuit breaker tripped? Check your switchboard for a tripped breaker labelled “heating” or “HVAC”
• Is the controller/thermostat display lit up? If the display is completely blank, the unit has no power

🔥 Check the Gas Supply

If power is fine but the heater still won’t ignite, check whether other gas appliances in your home are working — your stovetop or hot water system. If those aren’t working either, you may have a gas supply interruption. Contact your gas provider.

If other appliances are working fine, the gas issue is isolated to the heater — likely a faulty gas valve, blocked burner, or ignition failure. These require a licensed gas technician.

🌡️ Check the Thermostat Settings

This one sounds obvious but it catches people out every year:

• Is the thermostat set to Heat mode (not Cool or Fan Only)?
• Is the set temperature higher than the current room temperature? If the room is already at or above the set point, the heater won’t activate
• Has the clock or timer been accidentally set, locking the heater out of its operating window?

🧹 Check the Return Air Filter

A heavily blocked return air filter can cause the heater to overheat and trigger its safety limit switch, shutting the unit down before it properly starts.

Find the return air grille (usually in a hallway ceiling or wall), slide out the filter, and check it. If it’s clogged with dust and debris, clean or replace it, then try the heater again. This is a DIY job — no tools required.

🚨 Fault Codes on the Controller Display

Many modern gas ducted heaters display a fault code when something is wrong. Check your controller or the heater unit itself for any flashing lights or error codes.

Common fault codes that cause a no-start condition:

• Ignition failure — the heater is trying to light but failing (gas valve, ignitor, or flame sensor fault)
• Limit switch fault — the heater is overheating due to restricted airflow
• Flue or pressure fault — the combustion airflow is blocked or the flue is restricted
• Communication error — the controller has lost connection with the main unit

🏘️ Older Melbourne Homes — Extra Considerations

Many homes in Melbourne’s inner north and west — suburbs like Essendon, Brunswick, Moonee Ponds, Footscray, and Yarraville — are running gas ducted heaters that are 15 to 25 years old.

On older units, a no-start fault is often caused by a failed ignitor, a worn-out gas valve, or a cracked heat exchanger that has triggered the safety cutout. These aren’t DIY repairs — gas components must be handled by a licensed technician.

📞 When to Stop Troubleshooting and Call a Tech

Book a service call if:

• The heater has power and gas but still won’t ignite
• There is a fault code on the display
• You can smell gas at any point
• The circuit breaker keeps tripping
• The heater starts briefly then shuts off
• The unit hasn’t been serviced in the last two years