Flue Gases

Steve_126

I have an EG-45 one pipe steam vented to SS lined chimney. After the boiler shuts down from a long run, I can hear what appears to be flue gases condensing and dripping down the chimney for a few minutes and then it stops. Is this normal? This seems to have just begun to happen as the weather has gotten colder.

Steve_126

Flue Gas Question

I have an EG-45 one pipe steam vented to SS lined chimney. After the boiler shuts down from a long run, I can hear what appears to be flue gases condensing and dripping down the chimney for a few minutes and then it stops. Is this normal? Does this condensed flue gas go back into the boiler and beocome corrosive? This seems to have just begun to happen as the weather has gotten colder.

Jim Davis_7

Yes these flue gases are corrosive and this is not supposed to be normal but many might say it is that is why you have to use SS liner. Steam boilers should run hot enough not to condense. The problem is the inducer fan does not have an adequate post purge cycle. Because of fictitious DOE energy ratings and post purge de-rates the efficiency over 5%(should be a normal part of venting, not a loss) and therefore manufacturers have to avoid using it.

Mark Hunt

Not fan assisted


the EG that is, so no post-purge cycle.

Sounds like the system needs a combustion test.

Mark H

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Edward A. (Ed) Carey_3

EG 45

John,

How old is the boiler?

Has anyone checked the casting to assure that there is not a hole in the casting above the water line, (discharging steam up the chimney)?

If the above can be confirmed and you are SURE that the casting is sound.....

Is this the first year you are using the chimney liner?

Is the chimney on the exterior of the home?

Have any openings formed in the chimney, (loose clean out door, missing bricks, etc.)that could introduce cold air into the chimney cavity?

Is there any insulation inside the chimney cavity surrounding the SS liner?

Thanks,

Ed Carey

Steve_126

My answers follow your questions. Thanks for the help.

How old is the boiler? < than 6 months

Has anyone checked the casting to assure that there is not a hole in the casting above the water line, (discharging steam up the chimney)? This would be unlikely and I don't see any white smoke or steam coming from the top of the chimney.

If the above can be confirmed and you are SURE that the casting is sound..... I hope so it was a brand new boiler.

Is this the first year you are using the chimney liner? It was installed days before the boiler.

Is the chimney on the exterior of the home? Yes.

Have any openings formed in the chimney, (loose clean out door, missing bricks, etc.)that could introduce cold air into the chimney cavity? It is a 90+ year old chimney that was never lined. They recommend a SS liner for flue gases to prevent CO seeping into the house due to openings.

Is there any insulation inside the chimney cavity surrounding the SS liner? No.

Thanks.

Edward A. (Ed) Carey_3

Chimney

John,

How high (tall) is that chimney?

Ed Carey

Mike T., Swampeast MO

Have you visually verified that condensate is coming down the flue? The sounds of dripping water are notorious for appearing to come from a place other than the actual origin. You could be hearing condensate returning to the boiler...

Steve_126

No good point. My reasoning for thinking the flue gases were condensing and dripping back down the liner was because I could clearly hear the drip sound when I was near the fireplace. Maybe it is condensate coming back to the boiler from the riser and the sound just reverberates. Also I have a vent damper which is supposed to keep the heat in the boiler once it shuts off, so I assumed this could be creating the flue gas condensing situation.