MPD Vs Primary Air

freetown fred wrote:I keep my MPD 3/4 closed all the time in cold weather--even while tending. I've got no mano, no baro, no thermo's -- what I do have is an 1800 sq. 200 yr old farm house that the old HITZER keeps at 72*. So much for my scientific feed-back.

Im jealous! If I had the same stove as you that is what I would do too (except Id have a thermo). I would love to know what draft your chimney pulls as it must be very steady, although when wind blows (if that increases your draft) and if it warms up your stove you likely need the extra heat anyway, so the gadgets are pointless. I understand. An advantage of your stove with the excellent intake flapper it has.

But a lot of us get bored, want to experiment, have too much draft, or don't have an auto intake damper

There must be treatment available Mike

When I had my HomeComfort range--my MPD never got closed at all. Like stated MA, recognition is the first step!!

scalabro wrote:

Sunny Boy wrote:Try that on my range and you'll be setting the CO alarms off for sure. Been there !

The fire WANTS to breath. If you don't give it the chimney YOU WANT, it will find another ...... which might be through any and all leaks above the firebed in the stove and stove pipe leading to inside the house.

Paul

Well if my baseburner had four miles of gas path I would expect that! Wink, wink

...I have a feeling we're all sitting in a circle waiting for a smoke break, bad coffee and day old doughnuts.

michaelanthony wrote:...I have a feeling we're all sitting in a circle waiting for a smoke break, bad coffee and day old doughnuts.

Help has arrived....this place is sick, it's legal crack!

http://www.donutdip.com

Hmmmmmm

I got the coffee guys!...sorry for the drift Scott
http://www.peets.com/coffee/featured-coffee/all-coffees.html

scalabro wrote:I think I was misunderstood

This is with running the primary fully open.

I have not recorded numbers but it seems the stove will only accelerate out to "X" temperature for any given draft number with a fully open primary.

I have not had the balls to run wide open primary air and .06 draft

Oh and my draft numbers will not change via primary settings....until the stove heats more and creates more draft. Stove draft is primarily a function of MPD setting.

I don't think I misunderstood what you are doing.

the fact that you are aware of the issue of the stove getting .06 or more with wide open primary ( intentional or not ) suggests the validity of my point.

the stove may "only" run up so far at a set amount of open MPD, UNTIL there is MORE stack draft than you expected or wanted. this is something you can not deal with unless you are present to monitor.

i'm pretty sure your draft #'s will change as a result of primary opening and here's how to test it.

get your stove to moderate cruise temp. close all secondary, set your MPD to 45*, set your primary somewhere in the region of 1/3 open.

let the stove stabilize it's barrel temp. when the temp. stops moving, keeping your eye fixed on the Mano. close the primary by 50 % of it's setting. the Mano. will register higher. reopen the primary to original position the Mano. will return with it.

now, while watching the Mano. open the primary about the same amount you closed it before, the Mano. will sink.

try it, it's fun. I learned it from Lightning while working on draft with FRANK, don't know if he remembers but I know he knows the WHY behind it.

its certainly a good observation and its even better that your playing around and getting intimately involved with how the stove works.... BUT... I think we all agree its not the practice you should rely on (its not the intent of the design either for good reason)... long term your going to want to learn your primary air adjustments in the same way your learning the MPD function now. Use your primary air to control the heat output of your stove (use the MPD to control the draft)...

dcrane wrote:its certainly a good observation and its even better that your playing around and getting intimately involved with how the stove works.... BUT... I think we all agree its not the practice you should rely on (its not the intent of the design either for good reason)... long term your going to want to learn your primary air adjustments in the same way your learning the MPD function now. Use your primary air to control the heat output of your stove (use the MPD to control the draft)...

Ummmm yeah....

I said a few posts back that I noticed it while playing around

************

I can get more then 1.2 draft as my gauge pegs with the MPD open and the primary open or shut.

The two are not effectively related except for laboratory ops

And to set the record straight.....closing the primary may only (varies on every stove/chimney install) raise draft due to the increased resistance to incoming air through the primary openings, because for the short term draft will remain "X" ... this further increase applied stove draft. It's like sucking on a straw with a closed end...FACT!

Problem is IF it does on my setup it can not be seen on my draft gauge because it is does not have as fine a scale as a Dwyer.

The MPD is the primary control of applied stove draft.

I didn't want this to turn into slap down, Or another ad-nauseum draft thread. I simply wanted to know if anyone else has noticed this with their stove...

This may help with the head scratchin
https://en.wikipedia.org/wiki/Bernoulli%27s_principle

michaelanthony wrote:I got the coffee guys!...sorry for the drift Scott
http://www.peets.com/coffee/featured-coffee/all-coffees.html

Ok, Ill meet you at the Kittery Trading Post

michaelanthony wrote:This may help with the head scratchin
https://en.wikipedia.org/wiki/Bernoulli%27s_principle

Yeah, me and Mr Bernoulli visit every morning for coffee & donuts at the hanger

Here's a shot when all the birds were back in the barn...I think it was late November.