Chimney Liner Sleeved Wrong?

[Mike Lamb]

I have seen this a few times and have never found any discernible problems with the venting. This is a view of a chimney liner from beneath.

I have seen this same contradiction in prefab fireplaces before and called the manufacturer about it, and have been told this is the way it is done for that gas appliance.

In this case it is the chimney liner for 20-year-old furnace. The chimney runs up the middle of the house.

The lower vent pieces are sleeved over the upper ones which is wrong. Right?

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[ghentjr]

It is ok because anything that flows back down the flue will will stay in the pipe, not flow to the outside of the pipe.

[Marc]

I agree. Flue pipe seams aren't intended to be airtight so a little flue gas will get out regardless. The liquid condensates need to stay in the pipes.

Marc

[Rob Amaral]

Intuitively, it seems kind of wrong Mike, but it is better that exhaust condensate drip back and not 'out' the seams.. so..

Also, the draft of a center-located chimney with a liner is pretty dang strong... you might be able to detect a suction at those joints due to the strength of the vertical liner's draft.. How tall was the house.. ? The taller, the stronger the draft..

[Mike Lamb]

It's a two story home. I have seen this in homes with outside chimneys and not seen problems either. I never knew this is the way it is "supposed" to be done with a Cat 1. Or maybe it doesn't matter.

These days all liners around here are flex AL so there isn't much to see when you look up the clean-out other than to see if the new liner was installed.

[Hearthman]

That is a "male-down" joint and is required for solid fuel venting. It makes sense for managing all condensate but should be referred back to the mfr. of the liner. I don't see any screws or rivets joining the liner sections so it can disconnect. I would want to know if this is stainless steel because it is discoloring and may be corroding. In general, all liners must be listed to UL 1777 and installed in accordance with that listing for the type of fuel and application.

I hope you haven't see chimney liners in factory built fireplaces.