I guess I need a damper. Dwyer Mark II results

[John Lehet]

So, if I've done this right, my suspicion that my draft is crazy strong seem to be confirmed.

0F exactly outdoors on an accurate weather station off the deck
Stove is coaling, damper shut all the way down on Progress Hybrid, IR thermometer shows exterior of stove pipe about 10 inches up from stove is 225
The liquid is at zero before I plug it into the pipe
Put probe into hole about 30 inches up:

 

[Whitenuckler]

So, if I've done this right, my suspicion that my draft is crazy strong seem to be confirmed.

0F exactly outdoors on an accurate weather station off the deck
Stove is coaling, damper shut all the way down on Progress Hybrid, IR thermometer shows exterior of stove pipe about 10 inches up from stove is 225
The liquid is at zero before I plug it into the pipe
Put probe into hole about 30 inches up:

I'm not sure what that reads? I wonder if you make the zero position somewhere else to the right, you could get a bigger negative reading? I made my own from a look of clear hose so that would not be an issue on mine.

 

[John Lehet]

It seems to read basically off the scale negative! I plug it in and watch it drop below the scale from zero...

 

[John Lehet]

Also emailed this to Woodstock, but the way they are off and on with email these days I'm not sure I'll get an answer from them.

 

[Whitenuckler]

It seems to read basically off the scale negative! I plug it in and watch it drop below the scale from zero...

If you plug the other port in (if you can) it will go the other way on the scale and you already know it's a vacuum

 

[brenndatomu]

Yup, plug the hose in to the right hand port and you'll get a reading on the right side of the scale...and yes, it's still accurate that way, just "labeled" wrong on the meter (for the way we use it)
Make sure the Dwyer is level/plumb...that will affect it if not.
It does appear that you have plenty of draft though!

 

[John Lehet]

Other port

 

[brenndatomu]

I think -0.06" WC is considered within normal for most stoves...

 

[John Lehet]

That last one, stove still coaling with damper shut, stove pipe down to 173 exterior, now up to 8F outdoors

 

[brenndatomu]

That last one, stove still coaling with damper shut, stove pipe down to 173 exterior, now up to 8F outdoors

Oh...yeah take a reading after you reload and the fire is well established, any flue dampers wide open, but the stove damper set to your normal "cruise" setting

 

[Highbeam]

Is your 225 read on single wall pipe? So actually 450 inside? Seems pretty high for an efficient stove in the coaling stage with the intake damper shut.

I always thought you were supposed to read draft strength at high burn. I would expect a big difference from high burn to damper shut with a few coals so you would want to verify that you are comparing apples to apples.

 

[John Lehet]

Yeah, single wall pipe, stove full of coals no flames when I did that. But everything hot. I’m not sure, but I think the Progress with a firebox full of coals is hotter than an iron stove in the same state. Sure feels hot anyway, while my old Jotul was definitely at “better add wood!” When coaling in cold weather.

I’ll try high burn next. I burned 18 pounds of wood 5.5 hours ago and it’s still well over 70 in here, stove still heating enough.

 

[brenndatomu]

I always thought you were supposed to read draft strength at high burn

You can, but it doesn't mean much in this scenario. IME on most chimney it won't change that much anyways.
I would want to know the draft reading when the firebox is up to operating temp and the stove damper is set where it is normally for "cruise"
It may be a bit higher when in high burn after loading, it may drop a bit once you hit coaling stage, but likely not a lot.
If the stove is usually set at a certain spot for most of the burn, that's where you want to check it.

 

[begreen]

Other port

That's much more like it. This reading is normal and good. In order to define the worse case scenario, test at different stages of fire, especially with a hot fire after a reload with the air open much more.

 

[John Lehet]

A smaller fire (12 pounds of wood) with warmer temp but wind, with flame in the firebox, some secondaries.
The line moves with the wind, between .05 and .07

 

[begreen]

A smaller fire (12 pounds of wood) with warmer temp but wind, with flame in the firebox, some secondaries.
The line moves with the wind, between .05 and .07

If that trend continues at cold outside temperatures then it doesn't sound like a damper is warranted.

 

[Highbeam]

12# of wood seems like just a couple of splits. The interwebs say 45# per cubic foot of dry oak and the PH is supposed to have a 2.8 CF firebox so your 12# is only a 10% charge of fuel. Does that sound right? Do you think that when you actually load this thing up that the additional fuel will make a difference?

This far, the draft measurements are looking really good.

 

[John Lehet]

Oh, a bigger fire is much bigger. If I squeeze 30 pounds of hardwood in there it gets quite hot. Even the dialed back just-some-secondaries with a big load will really throw serious heat.

A 12 pound load is OK on a good bed of coals, but you wouldn’t start a new fire in a cold stove with that. There is always a good bed of coals, this winter,

 

[spudman99]

Here is my experience. I have a BK Princess 29 insert. 30' brick exterior chimney. Insulated liner. Right now the stove is full coals after a 12 hour burn, no flames. Thermo set at full open. Damper 8" above stove is 90º closed. My manometer still reads 0.16 water column.

Specs for this BK are 0.08wc. I have never gotten close to that when burning. My stove still works fine, puts out heat and gives me 12-14 hour burns with ease. So I am not sure how much of a difference the higher draft will make on a modern stove, in my case not much.

 

[begreen]

Stove pipe dampers don't seal 100%, intentionally. The pass about 25% of the flue gases when closed. A 30' chimney may require 2 dampers, or closing off some of the openings in the damper blade.