When it comes to water heater troubleshooting there are several things that you should keep in mind. You will need to be ready for every possible scenario and always have the number of a professional nearby just in case. A yellow flame is an indication of a weak flow. Check these tips to determine if you can fix this yourself.
Scale on Burner
You may find that with a yellow flame on your water heater that there is a scale that is on top of your burner. If this is the case, the best thing to do is turn off the heater and give it time to cool off. Once you have done this then clean off the burner plate.
Dirty Burner Orifice
If you think that your burner orifice may be dirty, you will simply need to remove it and look at it in the light. If it looks dirty, simply wipe it clean.
Clogged Flue Way
Your flue could be clogged if you see a yellow flame. If this is the case, you will need to take a good look at it and clean it thoroughly.
An easy fix is the gas pressure, which may only need a simple adjustment.
If none of these do the trick, you may need to call a professional.