Alderlea t5 outside air intake

[EllisB]

I have been enjoying all the great info on your forum, but I'm hoping someone can help me out with some info on the outside air connection on the PE Alderlea t5. I have a new unit being delivered in a few days.

My plan is to sand and paint a piece of 4" galvanized ducting to connect to the stove, which will extend down through the hearth (4 1/8" hole) and connect to flex ducting that will be run to an outside vent. One question is how is the ducting secured to the stove? Is there a female or crimped male fitting already attached to the stove under there? A second question is about the max run of this intake. I will have at least 10' of ducting and 2 90 degree turns. If that seems like it might be too restrictive I could increase to 6" once it's under the floor.

Does anyone happen to have a pic of the underside of this stove?

Many thanks!

 

[Mark Richards]

Before installing an OAK do a bunch of research online about the effectivness of these things. I was going to do it but came across information that made me change my mind and I didnt install it. The reason for me was the issue of pressure differences created by strong winds and I live in an area where they install those wind turbines (Damn Eagle Killers!!) so it didnt make sense in my neck of the woods.

 

[Sprinter]

Do you need to run the duct to the outside? If you can terminate it under a ventilated crawl space, that's perfectly acceptable and it would also eliminate any potential wind problems. The manual doesn't give a max run, but 10' with a couple of 90's doesn't seem excessive. Figures I see for wood stoves are around 20 - 50 cfm air draw. You could check with PE to be sure. And maybe with flexible duct, you won't need 90's.

 

[EllisB]

Thanks for replies. Sure, there are some entertaining pieces supporting and criticizing the use of outside air.
For: (broken link removed to http://www.chimneysweeponline.com/hooa.htm)
Against: http://woodheat.org/the-outdoor-air-myth-exposed.html

I guess my final decision to do OA came down to the fact that we have a hard time getting a fire going or keeping it going when all the windows are closed, and it takes right off when the window near the stove is cracked. Our house is a 1950's all block ranch with newer insulated windows (see pic below...yeah, I know, it's a work in progress), so it's not drafty at all. Unfortunately, I don't have a good way to know how the new stove will compare to the old, but since the OA install will be impossible once the stove is set (at 500 lbs, I hope not to move it again soon) I figured I'd do the work and if it doesn't work out I can always closed it off.

I have a full basement, so no crawl space. I haven't seen anything that can really be done about the wind issues, but I did see that putting a backdraft damper at the end of the line can help make sure the stove doesn't backdraft out the intake and create a fire hazard. I thought something like this (http://www.deflecto.com/advp/products/pc/catalog/techsheets/B_D_0_4_t_p_s.pdf) installed backwards where the flex terminates at the basement wall would work.

Thanks again for the helpful comments,

 

[KodiakII]

I am going to run one into my basement. There is an oak already in place for my oil furnace that should benefit my stove also.

 

[Sprinter]

I guess my final decision to do OA came down to the fact that we have a hard time getting a fire going or keeping it going when all the windows are closed, and it takes right off when the window near the stove is cracked.

That's a classic case for OAK. In a fairly leaky house, it doesn't matter as much, but imagine what it would be like with some fans and a clothes dryer running. I can't comment on the Deflecto device installed backwards, but it could be a potential source of problems if it malfunctions. I'd be more inclined to leave it out unless you need something like that.

 

[KodiakII]

^^^^X2
That deflecto thing looks like a potential source of aggravation to me.

 

[Sprinter]

^^^^X2
That deflecto thing looks like a potential source of aggravation to me.

Yeah, I'm guessing it may not even open with the low pressures involved with a wood stove, especially operated down low. My suggestion would be leave it out.

 

[thechimneysweep]

The knockout on the bottom of the T5 is a tight fit for 4" corregated aluminum dryer vent. Stuff it in and it will stay there. If you're a belt-and-suspenders guy, you can put a bead of hi-temp silicone sealant at the join.

You can view a drawing showing the location of the T5's OA knockout at (broken link removed to http://www.chimneysweeponline.com/cpacaldert5.htm). A 10' run will be no issue.

 

[EllisB]

The knockout on the bottom of the T5 is a tight fit for 4" corregated aluminum dryer vent. Stuff it in and it will stay there. I

Thanks, this helps. I had found the diagrams on the chimneysweep website (actually, your website is where I first noticed the Alderlea), and they have been very helpful for making my plans. Ordered the diamond hole saw this morning, hopefully it gets here before the stove does.

Good points about the backdraft damper. I thought the recommendation to use one in this article (http://www.greenbuildingadvisor.com/blogs/dept/qa-spotlight/how-provide-makeup-air-wood-stove) made some sense, but I wouldn't use the one they suggest because it's made of flammable fabric (http://tamtech.com/userfiles/cape damper tech data sheet.pdf). One related question, how about a manual damper to close down the air intake during the off season? Is there any concern with keeping it open year round?

 

[DougA]

I'm looking at replacing an old VC stove with a newer one with outside air. We live in a newer house that was designed to be airtight and even though we currently rarely have problems with draft, my theory is this: The air for combustion has to come from somewhere - simple physics. I would rather have it coming from a controllable outside source than leaking in through every crack and door jamb in our house. When it does that, you've got a cold draft that is not pleasant to live in. I can easily feel the cold draft coming into the room when the stove is on if I'm sitting on the floor near the doorway. Even if your house is tight like mine, it will find a way.

To answer your other question, the air is being sucked through your vent, not being pushed so it will draw what is needs to and the length and elbows will make less difference than if the air was flowing out from the stove. If in doubt about the connection, email Pacific Energy and ask. I emailed them last week and rec'd a complete answer within hours on a question I had on design changes.

 

[EllisB]

Thanks for the comments Doug.

I got to work this week and built a new up-to-code hearth for the new stove, but now I have a possible change in my air intake plans and would be happy to hear any comments for or against.

As I mentioned in my first post, my original plan was to duct down through the hearth and the floor and out a modified basement window. However, now that I have the 4 1/8 diamond grit hole saw, I'm considering going through the block wall right behind the stove. This would significantly simplify the instal job, but my concern is that the wall is made of 3 x 11-1/2 hollow block (9 in. deep) (see pic) and I'm not too sure if this is a good idea. And if it's OK, what's the best location for the hole in relation to the block joints...or does it even matter?

 

[madison]

stupid question/comment, why does a hole in the hearth for an outside air duct, NOT invalidate ember protection for the hearth? (seems like bad grammar, sorry)

 

[begreen]

With an ember protection only hearth, what is to violate? It's at the back of the stove where heat shielding is not a big concern. All embers are going to come out the front of the stove and the hole is blocked by the pipe going through it.

 

[DougA]

Hope you have a decent drill. You'll need it, plus a steady hand and patience to get through the wall. Are you sure those aren't bricks with holes through them? Maybe in your area they are called blocks but we call them bricks and they will be much tougher to drill than a cinder block. However, can be done. Sorry, can't add any expertise on where to drill for that size of a hole. If I were doing it, I would aim for dead center of one of the vertical joints. That way, you have the least cut out on 4 bricks/blocks, so the least structural risk.
Make sure you know exactly where this hole is coming out on the opposite side. If in doubt, drill a 1/4" pilot hole first.

 

[EllisB]

I know what you mean, but it is cement block (I've never seen anything like it either). I've drilled a few 1" and smaller holes in it with a grit hole saw before and I have no worries about the Bosch diamond grit going through it.

 

[EllisB]

So, I took the less permanent route and went through the internal wall and down through the basement. The new stove comes tomorrow morning and time seems to be crawling along at a snail's pace.

 

[madison]

With an ember protection only hearth, what is to violate? It's at the back of the stove where heat shielding is not a big concern. All embers are going to come out the front of the stove and the hole is blocked by the pipe going through it.

Thanks, I was thinking the same, but was considering burning embers could find their way into any nook or cranny within a few feet of the stove, front, back side ...

 

[EllisB]

The stove is burning well on outside air. I ended up using rigid aluminum 4" ducting, which I painted with stove paint. The clearance under the stove where the air intake is located is only 4.25" and required a modified low clearance elbow. I cut tabs in the female inlet to get it narrow enough to fit under the stove and then bent the tabs out from the inside once I got into the air intake to secure it to the stove.

Thanks to everyone for the feedback on this project.

 

[DougA]

I'd be interested in knowing if it burns better with outside air or if it makes no difference. Of course, if the connection is easy to take off.

 

[raybonz]

The stove is burning well on outside air. I ended up using rigid aluminum 4" ducting, which I painted with stove paint. The clearance under the stove where the air intake is located is only 4.25" and required a modified low clearance elbow. I cut tabs in the female inlet to get it narrow enough to fit under the stove and then bent the tabs out from the inside once I got into the air intake to secure it to the stove.

Thanks to everyone for the feedback on this project.

View attachment 121635 View attachment 121636

Stove and install look great, congrats! I've run my T-5 a couple years now and it runs OK with no OAK but a tight home might need it.. I did perform air reduction surgery as the flue and stove would get very when starting a full load and all is well.. Seems many see this issue and more than just PE might be affected.. There is simply too much air with the air all the way down at times..

Ray

 

[madison]

With an ember protection only hearth, what is to violate? It's at the back of the stove where heat shielding is not a big concern. All embers are going to come out the front of the stove and the hole is blocked by the pipe going through it.

BG,

Doesn't the ember protection need to be continuous for the entire dimensions of the hearth? ie a 4" hole for the outside air pipe coming up thru the "ember protecting" hearth would violate the requirement?