My carrier furance sometimes backfires like it is getting too much gas what could be the problem?

Could be dirty burners, gas pressure, cracked heat exchanger,or not venting properly. If the flame rolls out on start up it, probably dirty burners, Good luck, Mike

I agree with acetc. I would start with checking the burners for rust build up.

Actec, would you please contact me at your earliest convenience regarding my post at diy, Replace Honeywell with Totaline - DIY Chatroom - DIY Home Improvement Forum (http://www.diychatroom.com/showthread.php?p=182910#post182910) ?

Thank you,

Mark

Actec, My email address is [email protected]. Thanks

I also agree with acetc. Would also like to know more details about your furnace. How old? Natural draft, or draft induced. 80 percenter or 90+?

What you have is referred to as delayed ignition. You should contact a reputable service company in your area. If you do have a cracked heat exchanger then the problem is only going to get worse until the furnace will roll out. Could be very dangerous.

Do you have a flue dampener by chance? I have seen them on older systems and they can seize up and cause similar symptoms.

I agree mark, my main concern would be with carbon monocide. There may be a simple fix to your problem, but there may also be a very dangerous occurrence happening in your house. We are not there so we cannot rightly solve your problem. Please call for onsite help. Take care, and please let us know what you decide.

There is a pilot gas slot at the front of each burner, as the pilot lights one burner it lights the next until all of the burners are lit. If this little slot has stopped up from rust or dust the fire will not travel along the way it should, therefore the chamber that is not lighting the way it should has to overfill with gas until it puts enough gas out to reach the pilot slot. By this time the accumulated gas lights with a bang.

This may not be the problem is is just another suggestion.

Dead on info letmetellu, cross lighter bar could be dirty.