Gas heater flame colour is the clearest free diagnostic you have. Blue is healthy combustion; persistent yellow means something is wrong.
What a blue flame means
A crisp blue flame means the burner is getting the right mix of gas and air and the fuel is burning almost completely. Small flickers of yellow at the very tip are normal on some appliances, particularly decorative gas log fires designed to look like a real fire.
What a yellow flame means
A lazy, mostly yellow flame on a heater that should burn blue indicates gas heater incomplete combustion. The burner is starved of air — usually because of dust, lint, corrosion, a partially blocked flue or an incorrect gas pressure. Incomplete combustion produces carbon monoxide.
- Soot or brown scorch marks around the heater
- A sharp smell while the unit runs
- Heavy condensation on nearby windows
- Flames lifting away from or curling around the burner
What to do right now
Turn the heater off, open windows to ventilate the room and stop using the appliance until a licensed technician has tested it. If anyone in the home has headaches, nausea or dizziness that improves outdoors, leave the house and seek medical advice.
How we fix it
We strip and clean the burner, inspect the heat exchanger for cracking, clear and test the flue, measure gas pressure against manufacturer specification and finish with a carbon monoxide test. Call RapidFix Solutions for a same-day gas heater service anywhere in metropolitan Melbourne.