Why Has Your Gas Water Heater's Flame Changed Colour?

Posted on: 22 February 2019

The gas flame on your water heater is usually a steady blue colour. However, you look at the flame one day and see that it is burning more of a yellow or orange colour. Why has your heater's flame changed colour and what should you do about it?

Why Should Gas Flames Burn Blue?

Any gas flame should burn blue. This colour shows that the gas that is burning has the right combustion conditions and is safe. For example, a blue flame has the right mix of gas and oxygen in its supply.

If a gas flame changes to a yellowy or orangey colour, then this is a sign that something isn't right. The gas doesn't have the right composition or the right conditions to burn safely.  Any change in gas flame colour needs to be investigated.

Why Do Flames Burn Yellow or Orange?

There are a few reasons why gas flames change colour. This may be caused by a problem in your water heater or in the gas supply itself.

For example, gas flames need ventilation to burn safely. If your heater's flue or vents are blocked, then the system doesn't ventilate correctly.

Fumes may be blocked in and around the heater rather than being dispersed as they should. This may make your flame change colour. This can also happen if the heater gets too hot inside if its ventilation system isn't working right.

In some cases, the gas burner itself causes a colour change. For example, if the burner is blocked up with dust, dirt or soot, then the flames have to burn through these obstructions. This affects the way the burner works.

Sometimes, your water heater itself may be fine but you may have a gas leak. If your gas supply isn't working correctly, then the burner may be getting too little or too much gas.

What Should You Do Next?

If you can smell gas, then you may have a leak, and you need to move quickly. Turn off your gas supply, open windows and doors to ventilate your home, and don't turn anything electrical, including lights, on or off. Call your gas-registered plumber out as an emergency.

Even if you can't smell gas, it's still important to get your water heater looked at as soon as possible. You may have a tiny leak or a problem in your water heater that might get worse if left alone. Call your gas fitter, explain what the problem is and arrange for them to come out and fix it.