connecting hearth mount wood stove

When you have a T-connector the ash and creosote that naturally sloughs off during burning and during the heating/cooling cycle can fall down the liner and pile up in the lower extension of the connector. This keeps it from building up at the bottom of an elbow that is typically used with a thimble installation. If you are able to make the bend with the flex liner to simulate a 90 degree elbow you will need to keep an eye on this ash/creosote build up. If you can't visually look at that part of the liner from inside the stove somehow you will need to figure out how to do periodic inspections. When I had a different wood stove with an elbow at the back of the stove I would start to have draft issues when even a small amount of creosote/ash piled up in that elbow. Also, since that area is so close to the high temperatures of the stove top and perhaps even exposed to some flames under certain burning situations (depending on your particular stove) it can ignite and start a chimney fire if you don't have a clean flue.

Apart from that issue I wonder if SS flex liners are rated to take the sort of heat that would hit them when using the flex liner as an elbow? I would probably check with the manufacturer to see if the flex liner is rated to take that sort of heat. When you look at a SS T-connector it is clearly much more substantial than the thin flex liners. There could be a reason for this that relates to the high temperatures they are exposed to.

pen said:

Nick made a great post.

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+1

I was assuming a top venting stove, but realize you may be dealing with a rear vent.

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That's how my setup is. Flex into the back of a Fireview with ~ 90° bend and an appliance adapter.

pen said:

As long as you aren't flexing the thing so that it's sitting there day to day under pressure to make the connection, then I see no concern or reason not to.

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Define "pressure."
I wouldn't say that the bend is stress free, but it's a large-radius curve. I don't think that this is as rough on the pipe as the "ovalizing" that some do to get the pipe through the damper frame instead of cutting the frame out.

Nick Mystic said:

When you have a T-connector the ash and creosote that naturally sloughs off during burning and during the heating/cooling cycle can fall down the liner and pile up in the lower extension of the connector. This keeps it from building up at the bottom of an elbow that is typically used with a thimble installation. If you are able to make the bend with the flex liner to simulate a 90 degree elbow you will need to keep an eye on this ash/creosote build up. If you can't visually look at that part of the liner from inside the stove somehow you will need to figure out how to do periodic inspections. When I had a different wood stove with an elbow at the back of the stove I would start to have draft issues when even a small amount of creosote/ash piled up in that elbow. . .

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Yeah, when I clean the liner, the debris collects in the bend. With my stove, I just have to open the lid and reach back into the flue to scoop it out. If I had a different stove that did not allow such easy access to the flue, I would use a Tee. . .wouldn't want to disconnect the liner for cleaning. Haven't seen much debris in there between cleanings.

Apart from that issue I wonder if SS flex liners are rated to take the sort of heat that would hit them when using the flex liner as an elbow? I would probably check with the manufacturer to see if the flex liner is rated to take that sort of heat. When you look at a SS T-connector it is clearly much more substantial than the thin flex liners. There could be a reason for this that relates to the high temperatures they are exposed to.

Click to expand...

Good point, but if liners couldn't take the heat at the flue collar, they wouldn't be okay for use directly into inserts, and this is probably how most inserts are installed today.

So. . .the only difference I can see between an insert and a rear-vented hearth mount configuration would be the bend in the pipe, and the question is whether or not the bend could mechanically stress the pipe enough so that it would not be able to handle thermal stress. I ran the idea by my mfr, and he didn't have a problem with it. My setup has seen 3 seasons in this configuration, and my liner gets a good bit of heat when the cat bypass is open -- vents directly into the flue. No problems so far. I know this doesn't prove that my liner will last as long as it might in a less stressed configuration with a Tee, but no problems so far. . .and two less pipe joints to worry about leaking.