Recommendations on Existing Wood Stove

It's has to be done when the stove is running...by drilling a small hole in the stovepipe then inserting a sample tube hooked to a manometer...for most homeowners a Dwyer Mark II model 25 is plenty good enough...and not expensive...I have bought them off eBay for $20 before.

 

brenndatomu The stove shop did mine in June, stove was cold. like a blower door test almost.. they pumped hot air in it.

 

Hmm...that's a new one on me.

 

I heard that from BHoller, actually.
Even though she only has 15' of stack, my SIL's T5 still burns pretty hot. The single damper I already had in the pipe slowed it down a little. When I put a second damper in recently, that slowed it a little more.

Another advantage of keeping the chimney inside is that the flue stays hotter, and there's not as much creo deposited.
Unless there is a thick layer of glazed creo, a single pass is probably good enough. That's all I've done, with a poly brush from the top.
The only time I had chimney fires was back when I was trying to burn wet Red Oak, and the only time I cleaned pipe was when enough creo fell down to half block the elbow. When I noticed that the draft was dropping, causing smoke to roll out when I opened the door, I figured it was time to brush.
I'm no chimney-fire expert though. That would be BHoller . I think he scrubs the arse out of 'em with a rotary cleaner.

 

Brother-in-law works at the shop, and that’s how they measure in the summer; when nobody runs the woodstove.

 

Hmm...learn something new every day!

 

A gauge placed in a small hole drilled in the pipe

 

Testing in the summer won't tell you a thing to test properly the stove needs to be up to temp and burning with the air fully open. Any other test won't be at the manufacturers specs. So it won't tell you much of anything

 

I understand that they blow hot air into stove to check

 

Blowing hot air into a stove will not give you any idea what the natural draft is.

 

Ok but since it was my BIL who works for one of most reputable stove companies in state, and has over 12 years, and was later confirmed in December when stove was running. Because they happened to be here at Christmas. I will choose not to call him up to tell him he doesn’t know what he’s doing on your say so.

this was a “special” probably why I remember it 5 years later and not the gadget in pipe.

To be clear, it was a new chimney built on the exterior of the house. On a home with 3 different rooflines. He wanted to make sure draft was good. Stove was not running 2 numbers, measured in pascals, within +- 3 which he called close enough.

 

Ok I believe your bil did this test. But can you explain to me how blowing hot air that isn't hot enough to melt the plastic could in any way replicate the vacum created by the temperature differential between a hot fire in the stove and cold outside temps during heating season? It simply is not possible. No ammout of experience negates the basic principles of physics that creat draft in a natural draft appliance.

 

That's what was just going through my mind too...how to replicate the temp differential...suppose it could be done, but then what about modulating the volume of air...which would replicate the stoves air controls, and that would be different with every model...I'm not saying its impossible, but the more I think about this, its seems unlikely to give you a number that relates to real winter operating conditions.

 

Exactly. The only way you could get close would be to replicate the 1200 of so degree temperature differential and it couldn't be done by blowing anything into the stove either.

 

BHoller ok I texted him and because this is a family friendly I can’t just copy and paste.. I am not saying this too start anything. Just defending myself because you basically called me an idiot or a liar.

so this is paraphrased

Tell this person that draft is a mathematical formula that depends on 2 things!
1) height of chimney and 2) difference in air temperatures. It just so happens that we did test in morning before work and it was 58 degrees outside. Therefore we injected heat at 108* into sealed stove and machine measured draw up chimney. Only thing required is to have a difference in temperatures. Know outside temp and add enough heat to get draw, 40 to 50 Fahrenheit is kind of minimum. And if a plastic can’t handle 108° temperature and I damm well should throw out all my coffee cups..

moreover we basically install new chimneys all the time It’s kind of what we do usually not in winter and since most customers never burn good wood. Our goal is to make sure we have data that shows our chimney meets stove specs..

In short, for people with less common sense, The chimney is the engine of the car. If the engine don’t run (draw) car don’t go!

 

Well first off I did not call you a liar at all. I completely believe your bil did this test. All I said was that this is not a valid way to test draft. His assertion that draft is a combination of chimney height and temperature differential is true. But there are hundreds of not thousands of other variables that go into which simply cannot be accounted for with a simple mathmatical formula. Ask him how his formula accounts for the difference in house pressure due to stack effect. Of difference in density due to change in humidity inside and out. It just is not an accurate testing method.

And yes I install chimneys all the time as well. It is also my thing.

 

His comments are OK he’s “one of those”

1) I measure humidity with a hygrometer inside and out along with temperatures etc etc

2) I put a rough floor plan and enter data into this magical thing called a software app that estimates stack effect and other variables.

is this perfect no, In fact most chimneys I have build I can tell you whether they’re going to draft just on the type of house and size style of chimney.

your house is “non conventional” I wanted to be sure, so we tested, tell. @&$&$. That my guesstimate was off by less than 6% measured in pascals!

to those reading: he says Oh all I need to get an engine to start is air, spark and fuel. Once it’s running... then I tune it.

so I am done now sorry to OP for thread

 

Can he tell us what this magic app is?

To be clear I can generally tell if a chimney will draft well or not without testing. But what I can't tell without proper testing is whether or not that draft is within spec or wether or not one damper reduces it enough. What about 2 do I need to restrict the top as well to make the stove work properly.

 

I posted a question about this on several chimney pro boards and so far I have had roughly 25 responses saying they have never heard of such a thing. One of those resposes was from one of the leading csia tech instructors. I will report back with any interesting results.

I have to add I would absolutely love it if I were wrong and there is an easy reliable way to test draft without having to get the stove up to temp. It would make testing so much faster and easier

 

So reading between the lines here, that means that this hot air test method is just to get a rough idea what you are working with, then retest the actual draft during burning conditions, to verify and "tune"?