Install advice?

[benbirby]

Howdy folks!

Some months ago I bought a used F500 (V2) and I'm gearing up to prep for installing it. I have a lot of interior work to do so I'm starting to make my plans and I thought I'd ask for your opinions on a couple things before I get started. I've read a TON on here about the model, and also every single spec/install/info sheet Jotul has for it multiple times so think I have a pretty good grip on what I have to do.

The scenario:
My house was built c1880 and has many layers of changes that have happened through many previous owners. At some point the existing fireplace opening was filled with concrete and the (brick) chimney covered with drywall because the chimney was used to vent the gas appliances. I have recently changed my boiler and hot water heater to no longer use this chimney so that I can use it for the stove. My plan is to remove the drywall and any plaster and (wood) lathe that is covering the brick, cover the unsightly concrete-filled fireplace hole with tile, build a hearth pad in front of that with the same tile, and go into the chimney with a thimble about 4' up from the stove. I am also replacing the liner with an insulated liner and doing some chimney work above the roof line. The total flue height from the top of stove to the cap will be something like 15-20', I think closer to 20'.
I can give more details if people want but I just wanted to set the scene.

One question-
For the section of flue pipe that goes from the stove to the thimble (about 4' and then an elbow), should I use double wall pipe? In old houses where I've lived with stoves, that section was single wall and seemed to radiate a lot of extra heat. Those were also a much older style stoves and I want to do whatever it takes to run this new stove as efficiently as possible. I also think the F500 might err on the side of slightly too big for my house, so I'm not that worried about the extra radiant heat, but I just wanted to ask folks' opinion on this. I have been presuming double wall.

Another question-
I'm installing, as I said, in front of a brick and tile wall, no combustibles. How close can I put the stove to the wall? It's a tight room so every inch counts but I don't want to do anything stupid. It also came with a rear heat shield. Should I use it? Or would it be nice if the stove heated that masonry behind it a bit, sorta like a mass heater?

I'm sure I'll have more questions down the line (after I start demo), and maybe the answers to these questions are obvious, but thanks anyway for weighing in!

 

[begreen]

My preference is for double-wall stove pipe. It is superior construction and helps the flue gases to stay hot enough (>250ºF) to exit the chimney without creosote buildup. Let the stove provide the heat.

What is behind the brick wall? If wooden studs, then that is the nearest combustible that must be honored for the clearance requirements listed in the manual. If it is the mass of the old fireplace, then there are no clearance issues. However, if this is an exterior wall fireplace with exposure to outdoors then most of the heat will radiate outside. In that case the stud wall in front of it may help reduce heat loss.

Be sure the chimney is completely cleaned first.

 

[EbS-P]

Top venting I assume? Two 45s is better than one 90 but keeping it as close as possible to the wall a 90 might be better. If it’s really 15’ with two 90s that might not draft very well.

I think double wall off the stove is best.

as for heat shield I would use use it. Themal mass behind the stove is not as important as keeping the heat in the stove and therefore the room/house. You said the stove might be too big. Keeping the stove hotter lets you burn cleaner at lower burn rate.

 

[EatenByLimestone]

You didn’t mention a blower, but you may find you want one later. Leave some room for 1! It’s easier than having to redo pipe!

 

[benbirby]

My preference is for double-wall stove pipe. It is superior construction and helps the flue gases to stay hot enough (>250ºF) to exit the chimney without creosote buildup. Let the stove provide the heat.

What is behind the brick wall? If wooden studs, then that is the nearest combustible that must be honored for the clearance requirements listed in the manual. If it is the mass of the old fireplace, then there are no clearance issues. However, if this is an exterior wall fireplace with exposure to outdoors then most of the heat will radiate outside. In that case the stud wall in front of it may help reduce heat loss.

Be sure the chimney is completely cleaned first.

Sorry, shouldn't have used the word "wall." It's a brick chimney. The chimney is set inside the exterior wall of the house so any combustibles are all the way on the other side of the chimney.
Sounds like consensus is to use double wall! I'll go with that.

 

[benbirby]

Top venting I assume? Two 45s is better than one 90 but keeping it as close as possible to the wall a 90 might be better. If it’s really 15’ with two 90s that might not draft very well.

I think double wall off the stove is best.

as for heat shield I would use use it. Themal mass behind the stove is not as important as keeping the heat in the stove and therefore the room/house. You said the stove might be too big. Keeping the stove hotter lets you burn cleaner at lower burn rate.

Yes, top venting. When you say "two 90s" I'm guessing that includes the connection into the bottom of the liner? I know it's best to keep the flue as bend-free as possible but I thought coming straight up from a stove a few feet followed by a 90 into a thimble is a relatively common practice?

I was being conservative with my flue estimate because I couldn't remember last time I measured but I just went outside with a tape and it's more in the 20-25' range.

Thanks for the thoughts on the heat shield. Will use it.

 

[begreen]

Sorry, shouldn't have used the word "wall." It's a brick chimney. The chimney is set inside the exterior wall of the house so any combustibles are all the way on the other side of the chimney.
Sounds like consensus is to use double wall! I'll go with that.

In that case, the stove can be placed close to the brick without issue.