Where does an offset go?

[Oldman47]

I have a system I am installing and the chimney does not line up directly with the stove top flue pipe. I have assembled a pair of DVL 45º elbows with nothing between them and that gets everything aligned perfectly between the stove and the chimney. My question is should I put those elbows at the top or at the bottom of the double wall stove pipe?

 

[fossil]

Doesn't really matter to the stove system...put them where it's easiest, looks best to you, whatever. I have one offset like that clear at the top of a cathedral ceiling installation, and I have another one on my shop stove about 1/2 way up a 6' run. Rick

 

[webby3650]

The offset typically goes right at the top. It looks best and gets the maximum amount of vertical run before the restriction. It will draft better this way.

 

[Oldman47]

That makes sense to me webby. Right now I was planning on a straight shot from the stove top to a spot near the ceiling then the offset and right into the chimney adapter.

 

[begreen]

Our offset is right at the stove. We have 20' of straight up flue and it drafts well. This was done strictly as a visual preference. You hardly notice it, but look at the stove pipe shadow to see.

 

[Dakotas Dad]

Ours is and was, both stoves, right at the stove, no issues, but our chimney is 24' straight up run of triple wall in an enclosed chase after that..

Homestead:
(broken image removed)

Mansfield, custom one off offset box made by me.
(broken image removed)

 

[bholler]

Why did you need that offset box dakotas dad? I cant tell from the pic but it doesn't look that tight

 

[webby3650]

That makes sense to me webby. Right now I was planning on a straight shot from the stove top to a spot near the ceiling then the offset and right into the chimney adapter.

That is the most common way to do it. Sounds like you have a good plan.

 

[webby3650]

DVL elbows are about 4 3/4" of offset FYI.

 

[Oldman47]

Yes they are webby3650. I needed a total of about 9 inches and the back to back 45s got me there. In my case the offset was not front to back like the ones I see in these pictures but side to side. I needed to get around combustibles with adequate clearance but there was almost no way to move the stove itself those 9 inches toward the right side. I have a basement stairway enclosure and was placing the stove centered on the back side of that enclosure on the main floor but the roof trusses did not line up well to allow that placement without the sideways offset. I had designed plenty of room in that location for a "future" stove and it really is a good spot for the heat to move freely around the living space. If I had moved the stove over that far to the side it would have required that the non-combustible pad intrude into a walkway so I did not consider that a reasonable option. One thing I had overlooked in the house planning stage was the need that a chimney avoid interference from roof trusses, it just never came up when I was laying out the floor plan. You always miss something with a new design and a house is almost always a one-off design. So far this is one of the few errors I have found and I am glad I can easily correct for it and not need to abandon my desire to burn wood. Since I am new to burning wood I am happy it is all that I missed in that respect.

 

[webby3650]

Yes they are webby3650. I needed a total of about 9 inches and the back to back 45s got me there. In my case the offset was not front to back like the ones I see in these pictures but side to side. I needed to get around combustibles with adequate clearance but there was almost no way to move the stove itself those 9 inches toward the right side. I have a basement stairway enclosure and was placing the stove centered on the back side of that enclosure on the main floor but the roof trusses did not line up well to allow that placement without the sideways offset. I had designed plenty of room in that location for a "future" stove and it really is a good spot for the heat to move freely around the living space. If I had moved the stove over that far to the side it would have required that the non-combustible pad intrude into a walkway so I did not consider that a reasonable option. One thing I had overlooked in the house planning stage was the need that a chimney avoid interference from roof trusses, it just never came up when I was laying out the floor plan. You always miss something with a new design and a house is almost always a one-off design. So far this is one of the few errors I have found and I am glad I can easily correct for it and not need to abandon my desire to burn wood. Since I am new to burning wood I am happy it is all that I missed in that respect.

DVL elbows back to back won't make 9", you will need a small section of pipe between the elbows.

 

[Dakotas Dad]

Why did you need that offset box dakotas dad? I cant tell from the pic but it doesn't look that tight

When I started the build, it was for a Jotul 602.. About the time I got serious, I was "informed" that I was installing a Hearthstone Homestead.. I didn't have much trouble with it, but used the elbows to keep it from being way back in the box. When we found that we were using the stove 24/7, it was decided the Homestead wasn't big enough. It would heat the house just fine most of the time, but when it gets down to single digits, it had to be run hard, and reloaded at 2-3am.. I like to sleep more now than I used to. LOL

So digging around on CL, I found this Mansfield, a few miles from my brother's house in NC, so made a trip down, grabbed it and brought it back. Sold the Homestead for about a $100 difference .

It's a few inches taller, and in order to not have to modify my already modified slip piece, I designed and built that offset box. It's bent up from 18g Stainless. Without it, or the elbows, the Mansfield would be against the back of the alcove, with no room for the fan and shield.. Mechanical engineer buddy of mine ran the numbers, it's only about 2% less efficient then the two elbows I was running. And I have tons of draft... so no issue. Plus it looks kind of cool and gives an good place to mount the flue thermometer.

DISCLAIMER:

I don't for a minute advocate people building their own stove pipe or chimney parts in the garage. I have a pretty wide ranging skill set, and lots of M.E. and E.E. buddies to keep me safe.. And I sleep with my insurance agent.

 

[begreen]

DVL elbows back to back won't make 9", you will need a small section of pipe between the elbows.

Correct, it needs a 6" piece between the elbows.

 

[bholler]

It's a few inches taller, and in order to not have to modify my already modified slip piece, I designed and built that offset box. It's bent up from 18g Stainless. Without it, or the elbows, the Mansfield would be against the back of the alcove, with no room for the fan and shield.. Mechanical engineer buddy of mine ran the numbers, it's only about 2% less efficient then the two elbows I was running. And I have tons of draft... so no issue. Plus it looks kind of cool and gives an good place to mount the flue thermometer.

I just hate offset boxes because they generally hurt draft and are a pain to clean but if it works well for you good job