A heater that won’t heat can have an electrical, gas, airflow or refrigerant cause. Our electricians check the supply and controls first, then the right licensed trade tests the heating side.
When to get it checked
Blank controller, no fan
The wall controller is dark, or shows a setting but no fan starts. That points to the power, the controller or the cable between them.
Fan runs, air stays cold
With gas ducted heating, air that stays cold once it’s been running a while usually means the burner isn’t lighting or staying lit. On reverse-cycle, check the mode; it may also be defrosting.
It cuts out or shows a code
It runs, stops, retries, then gives up, often with a code or flashing light. The code is your best clue to which part failed.
Soot, scorching or a different flame
Stop using the heater. Energy Safe Victoria says any change in how a gas heater runs, such as a new flame colour, means a qualified gasfitter must inspect it and check it for carbon monoxide leakage.
Why it happens
4 common causes
Power and controls
A tripped circuit, an isolator left off, a failed controller or a damaged control cable stops a heater before it even tries to start.
Ignition and flame sensing
A gas heater proves its flame before keeping the gas on. A worn igniter, dirty flame sensor or failing gas valve means it tries, fails and locks out.
Starved of air
A clogged return-air filter, a couch across the return grille or a failing fan motor chokes airflow. Gas heaters then overheat and trip their limit switch, and dirty filters can weaken a split system’s heating.
The outdoor unit and refrigerant
A reverse-cycle outdoor unit pulls heat from outside air; a failed fan, sensor or compressor, or a leak, stops it. Refrigerant can’t legally be topped up until the system is fully tested and every leak found is repaired.
What the job covers
What we usually do on this job. Your quote confirms it for your place.
- Symptoms and codes reviewed
- Controller, circuit, safety switch and isolator tested
- Return-air filter and airflow checked
- Ignition, flame and flue checked by a licensed gasfitter
- Outdoor unit, fans and sensors tested on reverse-cycle
- Fault explained, with the price before we start
- Full heating cycle run after repair
Your options, explained
Repair the failed part
Low disruption- Best for
- A heater in fair condition with one clear fault
- How it works
- The faulty igniter, sensor, controller, fan part or board is replaced, then tested through a full cycle.
- Worth knowing
- Older models can mean a wait for parts.
Replace the gas heater
Medium disruption- Best for
- An older gas ducted heater with a major failure
- How it works
- A new gas ducted unit goes on the existing ducts and gas supply, fitted by a licensed gasfitter.
- Worth knowing
- Energy Safe Victoria suggests considering replacement if a heater is old or hasn’t been serviced for several years.
Change to reverse-cycle
High disruption- Best for
- Homes that also want cooling
- How it works
- A split or ducted reverse-cycle system replaces the gas heater, which a licensed gasfitter disconnects. We also check whether your switchboard needs an upgrade.
- Worth knowing
- Price it beside a gas replacement. Old heating ducts may not suit cooling.
The people behind the work
Our own photos from jobs like this one. Family-run, based in Altona Meadows, with 19 years in the industry.
Licensed electrical contractor (REC 38187)See more team photos
Worth knowing before you book
- Photograph the code
- Codes often clear when the power cycles, so photograph the code and model label.
- Note when it fails
- Tell us if it only fails on cold mornings, at start-up or after a long run.
- Gas faults need a gasfitter
- The burner, gas valve and flue are work for a licensed gasfitter.
What affects the price?
The right scope depends on your installation. These are the details we check so your quote is useful, with any additional work explained before it proceeds.
Where the heater sits
A tight roof space or subfloor takes longer to reach than an outside wall.
How the fault behaves
A fault that shows every time is quicker to find than one that appears only on the coldest mornings.
The part
Igniters and sensors are common. Boards, fan motors and compressors cost more, and discontinued models mean hunting for parts.
Licences and extra findings
Some faults are purely electrical; others need gas or refrigerant work too. A cracked heat exchanger usually means replacement.
How it runs
- 1
Tell us the symptoms
System type, symptoms, any code and rough age.
- 2
Diagnose
Power and controls, then the gas or refrigerant side.
- 3
Price and repair
Fault and price before we start, then a test cycle.
Step by step, in more detail
4 steps
Start with the details
System type, symptoms, any code, rough age and when it was last serviced.
Rule out power and controls
We test the circuit, the isolator and the supply at the heater, then the controller and its cable.
Test the heating side
On gas heaters, a licensed gasfitter checks ignition, flame, gas supply and flue. On reverse-cycle, we check the outdoor unit, fans, sensors and, if the symptoms point there, refrigerant pressures.
Price, repair and test
You get the fault and the price before we start. After the repair, the heating runs a full cycle.
What is safe to do, and what to leave to us
Safe for you to do
- Check the controller is set to heat, above the room temperature.
- Reset a tripped safety switch once. If it trips again, leave it off.
- Keep the return-air grille and outlets clear.
- If you smell gas, or anyone gets headaches, dizziness or nausea while a gas heater runs, get everyone into fresh air and seek medical help if anyone is unwell.
Leave these to us
- Opening, relighting or adjusting a gas heater. Energy Safe Victoria says unlicensed gasfitting is illegal and potentially fatal.
- Running a rangehood or exhaust fan while a gas heater is on, which can draw carbon monoxide into living spaces.
- Topping up refrigerant, which needs a refrigerant handling licence, or opening up the outdoor unit.
When to get us in
- It locks out again after a restart
- A breaker trips when the heating starts
- Burning smell, soot, scorch marks or a changed flame
- Weak warm air, or a code that keeps coming back
More detail
Normal behaviour that looks like a fault
On cold, damp mornings a reverse-cycle outdoor coil frosts over and the unit stops heating to melt it, so the indoor fan goes quiet. Melbourne sits in the Cold zone of the Zoned Energy Rating Label, where performance in frosting conditions, below 5.5°C, is critical. After a defrost or a fresh start, the indoor fan waits for the coil to warm. Gas ducted heaters also hold the fan until the air is warm, and run it on after the burner stops.
Which trade the symptom points to
Faults in the supply, isolator, controller or control wiring are electrical, and our licensed electricians handle them. The burner, igniter, gas valve, flue and heat exchanger need a licensed Type A gasfitter, and a refrigerant leak needs a refrigerant handling licence.
Weak heat is a different problem
If the heater runs but the far rooms stay cold, the cause is often in the ducts. A duct that has dropped off its outlet in the roof starves a room, and so does a zone damper stuck shut. Close too many outlets and the heater can’t push its air out, so it overheats and cuts out.
Local rules and conditions
Victorian requirements and local conditions that shape this job, with the sources listed at the foot of the page.
Cold, still winter nights
At the Laverton weather station, July’s mean minimum is 5.2 °C, with June and August close behind. Mornings that cold bring more reverse-cycle defrost pauses.
Renting with no heating
Victorian rentals must have a fixed heater in good working order in the main living area. Failed heating is a legally defined urgent repair, which rental providers must make immediately.
Rental heaters from March 2027
From 1 March 2027, a rental heater that breaks and can’t be repaired must be replaced with an efficient electric reverse-cycle air conditioner in the main living area. Owner-occupiers aren’t required to switch gas space heating to electric.
Useful reading
Guides to read before you decide, with checklists and questions to bring to the quote.
- Gas ducted heater: repair or replace?How to weigh a ducted gas heater fault against the heater's condition, the ducts and the electric option, once the safety checks are done.
- Renting and the power or heating has failed: what to doNo power or a dead heater in a Victorian rental? What to check safely, what counts as urgent, how to report it, and what to do if nobody responds.
- An ageing gas heater: service, repair or plan an electric replacement?Separate immediate safety needs from a considered comparison of repair and reverse-cycle heating.
- Reverse-cycle air conditioning or gas heating?How each one makes heat, how it feels on a cold night in Melbourne's west, what Victoria's gas rules mean for you and what switching really involves.
Common questions
Questions people ask about this
- Why does my heater smell when I turn it on for the first time in winter?A dusty, slightly burnt smell on the first run of the season is usually dust burning off the heat exchanger, coil or element, and it fades.
- My rental has no fixed heater in the living area. Is that allowed?No.
Sources for the rules and local facts on this page
13 sources, with the date each was checked
- 1.Bureau of Meteorology: Mean minimum temperature (°C) 14.0 14.4 12.7 10.0 7.8 5.9 5.2 5.7 6.8 8.4 10.3 12.2 9.5 81 1943 2026 Accessed 30 September 2026.
- 2.Consumer Affairs Victoria: All rental properties must have a fixed heater (not portable) in good working order in the main living area. For rental agreements entered into from 29 March 2023, this must be an energy efficient fixed heater in the… Accessed 30 September 2026.
- 3.Consumer Affairs Victoria: Anything on this list is legally defined as an urgent repair: burst water service blocked or broken toilet system serious roof leak gas leak dangerous electrical fault flooding or serious flood damage serious… Accessed 30 September 2026.
- 4.Department of Energy, Environment and Climate Action (Victoria): From 1 March 2027, when a hot water or heating appliance breaks and cannot be repaired, it must be replaced with a heat pump water heater or an efficient electric reverse cycle air-conditioner (RCAC) in the main living… Accessed 30 September 2026.
- 5.Energy Safe Victoria: Check for changes in how your gas heater operates. For example if the flame changes from its usual colour. If there is any change, you must get a qualified gasfitter to inspect your gas heater and check it for CO… Accessed 30 September 2026.
- 6.Energy Rating (GEMS Regulator / DCCEEW): Dirty filters significantly reduce the amount of airflow and the energy efficiency of the unit. It can also impact the effectiveness of its heating. Cleaning clogged filters, or replacing a worn one, can lower the… Accessed 30 September 2026.
- 7.Australian Refrigeration Council (ARC), Fact Sheet 13 (ARC5225, 11/22): ‘Topping-up’ a system before the system has been fully tested and all identified leaks repaired by any individual is illegal. Accessed 30 September 2026.
- 8.Australian Refrigeration Council (ARC): A Refrigerant Handling Licence must be held by any person who carries out work in relation to refrigeration and air conditioning (RAC) equipment. Carrying out work in relation to RAC equipment means to do anything with… Accessed 30 September 2026.
- 9.Energy Safe Victoria: Gas and electricity are inherently dangerous and it’s illegal and potentially fatal for unlicensed and unqualified people to undertake any gasfitting or electrical work. Accessed 30 September 2026.
- 10.Department of Health (Victoria): When carbon monoxide is inhaled, it replaces oxygen in the blood, which may cause symptoms including tiredness, shortness of breath, headaches, dizziness, nausea, weakness, confusion or chest pain. Accessed 30 September 2026.
- 11.Energy Safe Victoria: Locate your electricity box outside your home and check whether the safety switch has tripped. If it has tripped, reset the switch. If the switch won’t reset, call a licensed electrician. Accessed 30 September 2026.
- 12.Energy Safe Victoria: It is recommended that ducted heaters are serviced every two years and during this service a CO test should be conducted at the heating vent outlets in all rooms. Accessed 30 September 2026.
- 13.Commonwealth of Australia (2019), 'The new zoned energy rating label for air conditioners—What installers and retailers need to know', hosted on energyrating.gov.au: Melbourne is in a black ‘COLD’ area—read the black Cold ratings. Accessed 30 September 2026.
