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FLAME BURNING IN BURNER TUBE

Ryan_6
Ryan_6 Member Posts: 3
The boiler is a Utica MGB series for hydronic heating and is burning natural gas , never converted to LP . I also cleaned between the sections of the boiler and burner tubes . I checked the orifices on the manifold and they were clean to . Checking from the draft hood built into the boiler jacket the chimney is pulling fine . The burner chamber doesnt vent all that well but the sections are clear as well as everything else . Could i adjust the gas valve to compensate for LP added to the natural gas mains ? and if so would that eliminate combustion inside the burner tubes . The gas valve is a honeywell vr8300 24v with standing pilot .

Comments

  • Ryan_5
    Ryan_5 Member Posts: 3
    Burner tubes

    When the flame ignites, it lights inside the burner tube. The gas valve and thermocouple have just been replaced. Why would it ignight inside the burner tube???

  • Ken_8
    Ken_8 Member Posts: 1,640


    Flames inside the burner rack(s) is almost always insufficient gas pressure - or if adjustable, improper air to fuel ratio.

    If non-adjustable air; the gas presure is probably too low.

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  • There are many things

    that can cause this and because of that, it is sometimes very difficult to diagnose the real reason the first time. As Ken stated, it is usually caused by a drop in available gas pressure before and/or after the gas valve. It can also be cause by insufficient combustion air, adverse chimney draft or a misdirected pilot assembly causing an improper burner lightoff. I more cases than not, it usually occurs with Propane and in the wee hours of the morning when it is real cold outside. More info regarding type of boiler, type of gas, type of chimney, etc. will help us all help you better. Hope this helps.

    Glenn Stanton

    Burnham Hydronics
  • J.C.A._3
    J.C.A._3 Member Posts: 2,981
    Just a little thing I learned.....

    We happen to live "seaside" and salt air wears out the orifice holes a bit prematurely.

    If the pressure is right and the feed to the gas train is right, I would look to replace the burner tube orifices with the originally speced ones. Maybe some aggressive chemicals in the vicinity of the boiler? Just a thought. Chris
  • Ryan what is your location?

    It may be that LP is not even mixed with natural gas in your area. Many parts of the country stopped doing that years ago. They now use LNG to cover peak shaving loads (extreme cold demand on gas system). If they are mixing propane and you make adjustments then you will have to go back after the mix is back to natural gas only and readjust.

    Try this, adjust the air shutters on the burners to a point where the flame just starts to turn yellow, then open the air shutters about a 1/4 more and see if the flashback stops. If it does not then slowly close the air shutters until it stops. Make sure those burners are good and clean and not warped or damaged in any way. Check all of the orifices and make sure they are not plugged. Check gas pressure ahead of the gas valve and after the gas valve.

    It is also a very good idea to take a combustion analysis on the system to make sure it is firing properly. A poor draft can often cause pressure differences in the burner combustion chamber.
  • Boiler Guy
    Boiler Guy Member Posts: 585
    Here's a good one

    Had a similar problem once. Changed out the burner assembly complete. Same problem. Turns out the owners got a new cat and placed the box next to the warm boiler. Found it was the ammonia offgassing from the litter box destroyed the air mix. Moved the litter box across the room ... problem solved. Boy did I feel dumb! Missed that kitty-little thing on 5 service calls. Only time I actually learned something from a Gas Co guy.
  • jim sokolovic
    jim sokolovic Member Posts: 439
    Buhhhhhhhhhhhh!!!!!!!!!!!

    How could you work with THAT next to the boiler?
  • peter desens
    peter desens Member Posts: 41


    Ryan,

    I'd like to offer my assistance in resolving this problem.

    As suggested by the other threads, there are a number of possibilities that could cause the flame to burn within the tube. If you could contact me at our office at, 1-800-325-5479 ext. 4128, I'm sure we can figure it out.

    Peter Desens
    Technical Service Manager
    ECR International - Utica Boilers
  • peter desens
    peter desens Member Posts: 41


    Ryan,

    I'd like to offer my assistance in resolving this problem.

    As suggested by the other threads, there are a number of possibilities that could cause the flame to burn within the tube. If you could contact me at our office at, 1-800-325-5479 ext. 4128, I'm sure together we can figure it out.

    Peter Desens
    Technical Service Manager
    ECR International - Utica Boilers
This discussion has been closed.