Flame Quality and Adjustable Venturi

RobO · October 2010

I have a Peerless 561 gas fired steam boiler. I just replaced the burner tubes in it after noticing two of the eight had holes burnt through them. The replacement was a straightforward process. I've started the boiler, and it operates normally. But I have two questions I hope somebody can shed some light on. And, I suspect they may be related.

1) The tubes have what appear to be an adjustable sleeve on the end of them where they slide over what I would call the gas manifold. I think they are adjustable because they have a slot in them that allows them to be slid back and forth. I had to transfer the sleeves from the old to the new burners as part of the replacement. I set them at the same position as they were on the original tubes. This was easy to do because they were all adjusted to the end of their slots, which is the maximum they could be open. My question is what is the purpose of this adjustment. And how do you determine the correct (optimum?) position?

2) The boiler documentation says the flames in the boiler should be blue. But mine have a lot of red in them. This was also the case before I changed the burners. Its what led me to discover the holes in the burners. I wonder if the adjustments have anything to do with the flame quality.

Thanks in advance for your feedback.

Steamhead · October 2010

You need to have a pro

set up that boiler with a digital combustion analyzer. That's the only proper way to do it. Try the Find a Contractor page of this site.

RobO · October 2010

Thanks for the quick response, Steamhead.

I have somebody lined up to come over and look at the system anyway. So I won't attempt to do any more with it. Based on my reading of Dan's Lost Art of Steam Heating, I think I have some fundamental near boiler piping issues. I'll have him look at the flame quality, too. But, I am still curious (sorry, a bad habit). I would still like to know the purpose of the adjustable sleeves. Are they adjusted as part optimizing the flame quality? What else could be adjusted as part of the set up?

Thanks,

Rob

Steamhead · October 2010

The sleeves

control the amount of "primary air" that is mixed with the gas going into the burner tubes. "Secondary air" is that which flows around the tubes and into the firing zone. The latter is not adjustable in almost all cases.

No adjustments should be made unless a digital combustion analyzer is being used. This is the only way to make adjustments properly and safely. If the contractor you are using does not have this equipment, find one who does.

Flame Quality and Adjustable Venturi

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