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Large gap btwn thimble + vent for oil fired boiler


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Is this installation okay? See photos - I have never seen a large space between a vent of an oil fired boiler and the thimble. The home was built in 1992. In 2006, a major renovation which included a new oil fired boiler was performed. The vent enters into the chimney through a much larger diameter thimble and appears to continue to run inside the chimney shaft, and all the way to the top of the 35' chimney. Even without the boiler running, there was a major cold draft coming from between the chimney vent and the thimble. I assume that the draft is coming down through the chimney from the top of the chimney, and had concern that exhaust would be drawn back down the shaft when the boiler is in operation.

Thanks for the advice!

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tn_2017321143214_Vent%20and%20Thimble.jpg

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tn_2017321143237_Chimney.jpg

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tn_201732114330_Boiler.jpg

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never seen oil fired down here

i'm aware of nfpa & csia that covers this

http://www.csia.org/oil_fired_chimneys.html

i'd note your concerns, request owner furnish seasonal/annual maintenance docs & refer client to someone competent & qualified to inspect & service the flue

my 2 cents

"appears" & actually does are 2 different things

are you willing to risk the flue not exhausting/exiting properly?

"assume" should not be any part of inspector jargon

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. . . I assume that the draft is coming down through the chimney from the top of the chimney, and had concern that exhaust would be drawn back down the shaft when the boiler is in operation. . . .

I share your concern, especially if its venting into the chimney in the middle picture, with the (probably unlisted) shroud at the top. There's no benefit to leaving the gap there. I'd advise them to have it sealed.

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Hopefully the vent connector is connected to a listed stainless steel flue liner inside the chimney.

The other issue I'd be concerned with is that with the drafting of air between the old flue and flue liner, the flue liner may not be staying warm enough for consistent adequate draft.

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Your photo of the vent into the chimney-breech area is not clear enough for us to fully help you... The bottom line is that ideally, oil-fired exhaust systems are 'tight' from 'exhaust outlet' of the appliance to the terminus of the exhaust (except for the movable barometric damper, 'if such a damper is required' by the boiler manufacturer"

.

Reason: So the oil-burner technician can properly 'tune' the oil burner.

This is all about 'proper draft control' of the burner-flame itself...so you can get maximum combustion..

I see sooty drip-stains at the top of that chimney.. which usually indicates the oil burner needs a tune-up..

Funky gaps at such connections, messed-up chimneys, loose clean-out doors and the like lead to poor control of the flame and inefficiencies in combustion and $$$ up the chimney lost..

A liquid fuel needs a good technician... think 'automechanic/1950's' :)

Again.. 'not enough info brother'.. :)

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