Question of the week 6/7/2015

Here’s how it works:
Must be an interNACHI member to win.

The Awards Committee panel member posts a question in the Education and Training section, once per week at a random time on a random day.

**All parts of the question must be answered in one post. You may not post more than once. ** The first(and only) post counts, get it right the first time.

Do not edit your posts as the Awards Committee can see that time stamp in the edited post…it just makes our sorting it out more cumbersome.

First correct answer (as judged by the question poster, and the award committee) wins. The lucky winner gets one case of “Now that you’ve had a Home Inspection Books” shipped to you. Courtesy of Nick G. Your prize will be shipped to the address on file.

“Question of the Week 6/7/2015”

A yellow flame indicates dirt in the burner, which prevents it from mixing the gas and air properly.

Soot indicate incomplete combustion


Yellow flame is a bad mixture of fuel and oxygen. Soot is an indication the gas is not all being burnt often indicating a leaking heat exchanger.

I would like to add that a yellow flame can also indicates high CO production. One cause– insufficient primary air opening.

Soot indicate incomplete combustion and can be very dangerous.

A yellow flame is an indication of a lack of oxygen while soot build-up is an indication of too much oxygen.

Yellow flame is caused by flame impingement regardless of the source (dirty burner, misalignment or anything cold in path of the flame)
Soot is the result of unburnt carbon.

  1. If burning natural gas, it means that the burner is dirty and not getting enough air.
    If burning propane gas, there will be a yellow “tip” to the flame, this is normal.

  2. There maybe a back pressure problem in the combustion chamber/ inadequate combustion chamber air supply therefore resulting in a carbon monoxide problem.

You can not add to your answer.

But this first answer is correct, You win David Asselin :smiley:

Congrats David!

Either one indicates that I’ve inadvertently traveled too far north and am no longer within my 60 mile radius in SW Florida.

WOohoo! Thanks,


Good Job David!!!