Gas Ducted Heater Not Working? Common Faults Explained

First, the safe checks

Before you call, three things you can check without touching the appliance:

1. Power and gas. Is the heater switched on at the isolator and the switchboard, and is the gas supply on? If other gas appliances are also out, the problem may be the supply.
2. The controller. Is it set to heat, with a set temperature above the room temperature? Are the batteries flat, if it has them?
3. The return air filter. A filter choked with dust starves the heater of air and is one of the most common causes of a heater that runs briefly and stops. If you can reach the filter safely and it is clearly dirty, clean or replace it.

Do not open the heater, work on the gas or electrical connections, or reset safety devices repeatedly. Those are technician jobs, and repeatedly resetting a heater that is locking out can be unsafe.

Heater not starting at all

Usually an ignition problem: a dirty or failed spark igniter or flame sensor, a control board fault, or a safety device that has tripped. If the controller shows a fault code, note it down; our error code guides explain the Brivis, Rinnai, Braemar and Bonaire codes.

Heater starts, then blows cold air

The fan is running but the burner is not lighting or is shutting down. Common causes are a flame sensor that is dirty, an ignition fault, a gas pressure or gas valve issue, or a heater overheating and cutting the burner because of poor airflow (often that dirty return air filter).

Heater switching off or cycling

A heater that runs for a few minutes and stops is often overheating because airflow is restricted, or a safety device is detecting a problem. Do not keep restarting it; book it in.

No airflow, or weak airflow

The fan, the fan motor or capacitor, a blocked filter, or a duct problem in the roof such as a collapsed or disconnected duct.

A smell of gas

Turn the heater off, do not operate switches near it, ventilate the area and call us or your gas distributor’s emergency line immediately. This is not a wait-until-Monday fault.

What we do when we arrive

One of our own in-house technicians diagnoses the actual fault, not the first symptom, and where practical repairs it on the spot: we carry a broad range of common parts. If the repair is bigger, you get the options and the price before anything goes ahead. We repair all major gas ducted heating brands and we do not push replacement when a repair makes sense; see repair or replace if the heater is getting on.

Most of the breakdowns above happen on heaters that have not been serviced. A yearly service before winter is the cheapest fix of all.