Gas manifold whistle on boiler

William Northrup

I have serviced a 20 - 25 year old U.S. National boiler that is natural gas. I have cleaned the burners that were half rusted shut. When I put the boiler back into operation I have a high pitched whistle when the burners are on, that was not there prior to the cleaning. I have checked gas pressure which is 3.5 inches w.c. Removed burner orfices and checked for obstructions and found none. Is it possiable due to the age of the boiler that the orfices need to be changed? Or what would you suggest?

Ken_8

The sound is coming

from a "flute-like" air split from the air shutter (assuming this old boy HAS air shutters on each rack).

The center of the rack must be centered on the orifice. If you turn the lights out and watch the flame, you may be able to see the flame lighting BEFORE it enters the rack! This will do a "flute" tune/whistle for sure.

3.5" w.c. may a tad high as well. Observation should get you where you need to be.

Good luck!



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William Northrup_2

Boiler Whistle

My whistle isn't coming from a flame in the burners.The burners run a normal flame pattern.The whistle seems to be coming from the manifold orfices. I actually took the manifold off and blew into the end of it and it would whistle out of the orifices no matter how hard or soft I blew into it. Do I need to plug and redrill my orfices? What do you think of this?

William Northrup_2

whistle not coming from burners

My whistle isn't coming from a flame in the burners. The Burners run a normal flame pattern. The Whistle seems to be coming from the maniflod orfices. I actually took the manifold off and blew into the end of it and it would whistle out of the orifices no matter how hard or soft I blew into it. Do I need to plug and redrill my orfices? What do you think of this?

Mark Eatherton1

Burners whistle when...

they forget the words to the song...:-)

Transformers humm when THEY forget the words to the song...

THe only humming/whistling boiler I've had to deal with was the Burnham natural gas naturally aspirated boilers. The whistle was coming from a flexible gas line that was used to connect the appliance to the boiler, and the humm, I'm not really sure where the heck that was coming from, but lowering the gas pressure from 3.5 down to 3 seemed to make it disappear. Try adjusting the gas pressure and see if it makes a difference. Just make sure you don't lower it to the point that you get flash back into the throat of the burner, or you'll hear what it sounds like when the devil gargles hot oil...

To their credit, Burnham did come out with a burner replacement that completely eliminated the humming coming from the flue gas collector.

I can't see what difference filling/drilling would have on the orifi's ability to inject gas quietly into the burner throat. That said, I did see a picture one time where a burner/orifice manufacturer showed a slight taper at the inlet to the orifice. One of them Dead Men things if you know what I mean..

Good luck and let us know what you find/learn.

ME

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