Carbon rings on endcone

Unknown

Every once in awhile as a technician I will come across a black carbon ring (like a doughnut)on the endcone. I usually knock it off with a large screw driver, change the nozzle, do a pump test and ensure that the ignition electrodes are set properly.

Today was my first one of these since I started my journey to becomming a pro, and this time I thought.... "What causes this?"

Any one know?

Thanks
- Norm

A.J.

Carbon ring on retension head

Norm check the Z diminsion on your draw assembly, if it is a Becket there is a plastic cap that you can use over the nozzle to help you set it.

Al Gregory

The blast tube is to far back probably

Burnerman

Both may be correct. I have had 2 occur on 2 different Heil oil furnaces. Both carbon rings started on the outer edge of the Wayne retention head and had a 1" hole in the middle from the 100#s of oil blowing thru it. One had the nozzle replaced that afternoon! A 70 degree nozzle an check of the nozzle adapter and "Z" dimension fixed both. NAS GAGE is the Plastic tool for checking "Z" dim on Wayne & Beckett burners without pullin the burner. I wonder if if the nozzle is the culprit in some cases? I never had to move blast tube position nor change Z dim on those two bad ones and we didn't have anymore trouble.

Unknown

I've had the same type of situation burnerman. I havent done anything major like moving the position of the burner tube or anything,.. but have never had the same problem twice at any one home.

Still loking for some science behind what causes this. If it is a Z dimention thing is it from to far forward, too far back,...?

Also I have had one person suggest that the endcone gets too hot and somehow that causes the problem.

Any other insights as to why and how this happens?

- Norm