Nat. gas flue Q:

MIKE6

I don't think a draft induced furnace was available 40 years ago.A gas gun,which would commonly replace an oil gun is not an induced draft furnace.That large draft hood is what many used to get the gas burner running efficiently.A double swing barometric damper doesn't give better numbers than the draft hood,most of the time.If its not broken i would not fix it.

Empire_2

Nat. Gas flue Question

I am looking at a 6" flue off an older, induced draft furnace roughly 40 yrs old. Currently there is a square box in the middle being use for what I would assume to be draft assist up the masonary chimney. Can I eliminate it and check draft to about .3 to .4 of should I install a barometric damper and look for more like .2 over fire and .3 to .4 flue draft? Flue only runs aprox. 6 foot to chimney. Customer does not want new equipment at this time.
Thanks. Also, there is no # identification to speak of.

Richard

flue

is the square box as round hole going all the way thru my be a stack robber, can you take a photo of the unit.

clammy

draft box

When i was younger and work for a company that had salesman that would sell jobs where the boiler specs would use a draft hood but would not fit into the basementbecause of height issues we would have our shop make us a draft divertor box instead of using the factory draft hood .I would guess it was a old timer or tin knockers trick i've hardly seen any one else doing them and if that is the case i would not remove it .In all likelyhood it was install because of issues mentioned above remenber your not suppose to cut a factory draft hood down i believe you lose the ul listing and rating if you do . If you remove it you may have to add a tee and a baromateric damper to correct draft while firing peaceand good luck clammy

Empire_2

Rich

no its 6" pipe into a box open on the bottom then exiting out with 6"round. I just can't emagine a diverter with induced draft. I could see it with a excessive run with a tjurland on the end. Then I would use the Barometric to allow the induce equipment to fire as designed without to much draw from tjurland. I cant help but think that there was some kind of a draft problem at one time.

clammy

yep

yep open on the bottom that is a draft divertor box could it be that there was essive draft acrss the boiler causing high stack or maybe to much draft across the burner the direct vent on this unit was a kit the boiler originally was natiral draft i am believing right if so the original draft hood may have been to high to hook up to your power venter that's why they may have used a draft box .I remenber in some towns we would have to get approval from the fire inspector which seemed to never be much of a issue but that was ovwer 20 years ago .All natural draft boiler that use a power vented or draft ascess must have the appalainces factory draft divertor hood at the correct lenght or the correct listed baromatric damper installed the draft box is probably alot cheaper but don't know about UL in this applacation .I did at one time have the mathmatical formula for sizing them but i do believe it's long gone info at least for me .Bud at the sheet metal shop site may still have peace and good luck clammy

Darin(in Michigan)

Maybe I missed it

The purpose of a draft inducer is not to assist in forcing the products of combustion out the chimney. The inducer is design to pull the products of combustion through the appliance and natural draft is supposed to take it from there. Seems strange to have an inducer on a 40 year old unit. What brand is it?

Empire_2

Yea

I dont know if the burner gun was added at a later date, but thats what I got. As stated before there are no decerning numbers at all. Regardles, I am going to rty it with and w/o a new barometric damper. I will be happy if I can acheive 2. to .4 neg draft before the damper.

Empire_2

Thanks

Thanks to all that replied. As much as I would like the customer to replace the unit, That will not fly now. I will check draft for safe operation and make reccomendations as to the need for updated equipment. They can only save money in the long run. Thanks again Mike T.