The Draft

[Berner]

Hey guys,

So I've read a bunch about draft and have a few questions about it. I understand that straight is better than bendy, interior (warm) is better than exterior (cold) and tall is better than short. However as everyone has said before there is no perfect stove just the perfect stove for your setup. Right now I'm trying to settle on a stove and I think I have decided on a progress hybrid however I'm nervous about my draft setup.

The setup: I measured approximately 16' 6" from the top of my chimney to the stove rear vent that I will using. I'm running the liner through an exterior mansonry chimney. The terra cotta tiles measure 7.25"x 12". After the rear exit from the stove, I have a short horizontal run to a 90 degree T. Then it's straight up a short run before two small bends (to get it through the fire damper area), 30 degrees approximately. Then I'm straight up the rest of the way.

My house is very oddly put together. It has been added onto and extended a few times. The chimney complies with the 2/10 rule but it is not the highest part of the house. It is probably 5-10 ft shorter than a dormered bedroom on the other end of the house. There is also a large Oak tree and several large evergreens that are close to the chimney.

With a few strikes against me I want to make sure I have everything else working in my favor.


Questions:

1) Rigid vs flexible: Is rigid better then flexible if I can get it down the chimney?

2) Insulating the liner: Is the liner tape wrap or pour in mix better? Is combining both of these the best option?

3) OAK. Would an OAK help the stove's draft? I live in an old drafty house. From my understanding the OAK would help with the draftiness of the house but necessarily the draft for the stove correct?

4). Are some brands of liner kits better then others?

5). Block off plates. Are these usually part of the liner kit or something that I would fabricate afterwards?

6). Is there some sort of test that I could do to determine if my draft is going to be sufficient?

7) Your draft runs your stove. Would a larger stove require more draft than a smaller stove to function properly? I like the PH for a lot of reasons I just want to make sure that I won't be banging my head against the wall trying to run something that won't work.

Thanks in advance for all your help.

 

[chimneylinerjames]

1) Yes it is better, you can install rigid for the top section then flex attached to the bottom of the rigid to get you thru the bends. Or there is also smooth inner wall flex liner.

2) I like the 1/2" wrap the best, it has the foil backing that helps alot with reflecting the heat back towards the liner.

3) You are correct. Every house/stove is different, so we can't say it will definitely help or not.

4) Absolutely, some use inferior metal alloys, use lower quality liner components, like the top plate and cap. Ask around for reviews of companies.

5) They are not part of the kit, you need to make one for your fireplace.

 

[begreen]

The best guarantee of the stove working correctly is to follow the manufacturer's guidelines. It sounds like you are doing that. I haven't read anything here so far that would make the PH a bad fit. But give them a call to verify. They have a good support system and want to ensure your success and satisfaction.

There are tools for measuring draft after you have the liner installed. A good installer or stove should have a magnehelic or you could pick one up on eBay for about $20.

 

[fire_man]

I have a similar setup to what you are proposing. I have a Progress with an external chimney 16 feet from stove's exit to the top. It's lined with a 6" rigid liner inside a 13 x 13 clay liner with a 2 foot section of flex pipe to get thru the damper area to the "T". I double wrapped the liner with 2 layers of 1/2" Foil Faced Olympia Super Wrap.

I did have some draft problems with this stove until I wrapped it. I solved the following issues after wrapping:

1. No more (or only minor) smoke spillage when loading - improved ESPECIALLY when outside temps >50 F. (and this is with the stove's annoying anti-smoke spillage baffle plate removed!)
2. Eliminated backpuffing (only very occasional now).
3. Glass stays really clean now much longer (weeks instead of days).
4. Checked flue after burning one cord and it's almost spotless, would have been lots of soot before.
5. No more smoke smell immediately after engaging cat -used to get a "sweet woody smell" after engaging.
6. Fire takes off MUCH quicker in warmer weather

From what I could tell from spotty manufacturer's literature and tons of phone calls, inch for inch, wrap has better "R" value than pour-in mix. I believe rigid is superior to flex for durability and draft - many installers will tell you otherwise but I think they are just plain wrong.

Best thing I did for this stove was to improve the draft - it behaves really nicely now and I love the stove.

I know what you mean by wanting to run a test before commiting, My Fireview ran fine with the old uninsulated setup but the Progress is pickier. You can always install another 3 feet of class "A" to extend the pipe if needed.

 

[Berner]

Thanks for the responses guys. Sounds like I will be ok.

I expect the terracotta to be slightly misaligned so I'm going to be lucky to get a single layer of the 1/2 inch tape around. Is this tape wrapped pipe something that I have to be nervous about deforming in the installation process? If I hit a misaligned tile will I be ok? Would it be best to use the pour in mix after wrapping the pipe?

Also anyone else have experience running larger stoves on less than ideal draft setups? Anyone run a smaller stove with success and change for a bigger stove with worse results using the same draft setup?

Woodstock recommends at least 14 ft of chimney. I'm ok with my 16.5 ft but only 2.5 ft more than the minimum doesn't give me that warm and fuzzy feeling. Though I'm not a fan of how it looks having an extra three feet of class A pipe it might be necessary. Is this something that I could add on later if I was unhappy with the performance?

 

[fire_man]

The Insulation is first wrapped around the pipe like a hot dog in a blanket, then the seams are taped, then a very thin stainless steel screen/mesh is slid over it to keep the insulation tight and together for the installation process. It sounds like you have a very tight clay liner and if it's misaligned that could be a problem with rigid, hard to say. I don't see how you would have room to use pour in mix after wrapping with 1/2" and I don't know that it would add much more R value.

I wonder if you should buy a cheap 4 foot section of stove pipe and try to drop it down to see how much room there is before buying SS Rigid? Second plan for me would be to line with smooth wall flex if Rigid won't fit.

There is an adapter that will allow transition from single wall to class A for the last 3 feet. Yes its something you can add later - you can always first try a cheapo 3 foot add-on of single wall to see if it further improves draft before spending $$ on class A and adapter.

 

[Berner]

The Insulation is first wrapped around the pipe like a hot dog in a blanket, then the seams are taped, then a very thin stainless steel screen/mesh is slid over it to keep the insulation tight and together for the installation process. It sounds like you have a very tight clay liner and if it's misaligned that could be a problem with rigid, hard to say. I don't see how you would have room to use pour in mix after wrapping with 1/2" and I don't know that it would add much more R value.

I wonder if you should buy a cheap 4 foot section of stove pipe and try to drop it down to see how much room there is before buying SS Rigid? Second plan for me would be to line with smooth wall flex if Rigid won't fit.

There is an adapter that will allow transition from single wall to class A for the last 3 feet. Yes its something you can add later - you can always first try a cheapo 3 foot add-on of single wall to see if it further improves draft before spending $$ on class A and adapter.

Good call on trying to drop a 4' section of cheap rigid before committing to the whole stack.

My terracotta tile is 7.25"X12". I'm hard pressed in one direction to get the 6" liner down with insulation but in the other direction I have lots of room to add extra insulation if it would help?

I think I will stick with the 16.5ft tall liner and add on the extra 3 ft later if need be.

 

[BrotherBart]

Paint cans are 6 1/2" to 6 5/8" diameters. They are good for lowering on a rope to check to see if a liner is gonna fit.

 

[chimneylinerjames]

If you can use rigid, that would give you an extra 1/4" of play. 6" rigid is true 6", 6" flex liners are 6.25". So if you use the rigid and 1/2" insulation you are looking at about 7" outside diameter. The flex would be right at 7.25"

 

[begreen]

If you get in a pinch. Duraliner will fit in there. It's a premium product, but very well made and pre-insulated. The liner is 6 5/8" OD and comes in flex or rigid.