MPD location

Re: MPD location

PostBy: ddahlgren On: Tue Mar 11, 2014 6:35 am

Gekko wrote:Read the last paragraph of Paul's post Fred.

I agree with Paul.

In my mind the ideal situation would be a chimney that completely radiates it's heat in the house to the point where the gasses exiting the flue are only hot enough to maintain a pressure drop across the coal bed sufficient to burn that coal.

A simple example would be a stove that is located in a basement with a stainless pipe that has a clear shot to the roof. It's entire length exposed to the inside of the house. Of course the MPD would be at the top of the flue, if it was even necessary.

I'd like to see a setup that uses a double wall stainless chimney pipe, where primary air is routed to the stove inlet via the entire length of the pipe. This would put lots of heat back into the appliance where it could radiate again.

Too much drift here now though!


Here you go..
http://www.duravent.com/Product.aspx?hProduct=23
ddahlgren
 
Hand Fed Coal Stove: Crane 404

Re: MPD location

PostBy: freetown fred On: Tue Mar 11, 2014 6:56 am

AND???? stated specifically for wood or pellet stoves--whole different critters--but yet this goes on & on & on :roll: Could you remind me WHY????????? again. This getting olds not all it's cut out to be toothy
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: MPD location

PostBy: ddahlgren On: Tue Mar 11, 2014 7:02 am

freetown fred wrote:AND???? stated specifically for wood or pellet stoves--whole different critters--but yet this goes on & on & on :roll: Could you remind me WHY????????? again. This getting olds not all it's cut out to be toothy


Read freetown fred it is listed for dura vent plus all fuel. Here ya go my mouse phobic friend your concern was solved one click away...
http://www.duravent.com/ProductCategory.aspx?c=8
ddahlgren
 
Hand Fed Coal Stove: Crane 404

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Re: MPD location

PostBy: freetown fred On: Tue Mar 11, 2014 7:45 am

Not concerned at all dd, I guess I'm just spoiled on that KISS concept--but thanx for putting up the SPECIFIC correct link for us, less then computer savvy folk :)
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: MPD location

PostBy: ddahlgren On: Tue Mar 11, 2014 8:26 am

freetown fred wrote:Not concerned at all dd, I guess I'm just spoiled on that KISS concept--but thanx for putting up the SPECIFIC correct link for us, less then computer savvy folk :)


No problem freetown fred, the first link did show the family but no fuel specs and the one with fuel specs did not mention the fresh air kit,. LOL
ddahlgren
 
Hand Fed Coal Stove: Crane 404

Re: MPD location

PostBy: JohnB On: Tue Mar 11, 2014 9:56 am

Note that the majority of the Duravent inner liners are made from 430 stainless which has far lower corrosion resistance then the 316 typically used for stainless chimney liners. Most liner sites recommend 316ti for coal applications over the standard 316 liners. I wouldn't expect the Duravent inner liner to be long lived when used with a coal stove.
JohnB
 
Hand Fed Coal Boiler: Hitzer 50-93

Re: MPD location

PostBy: ddahlgren On: Tue Mar 11, 2014 11:02 am

JohnB wrote:Note that the majority of the Duravent inner liners are made from 430 stainless which has far lower corrosion resistance then the 316 typically used for stainless chimney liners. Most liner sites recommend 316ti for coal applications over the standard 316 liners. I wouldn't expect the Duravent inner liner to be long lived when used with a coal stove.


How long would you guess? I wonder why Duravent says they are fine with coal? Just temperature rating maybe?
ddahlgren
 
Hand Fed Coal Stove: Crane 404

Re: MPD location

PostBy: JohnB On: Tue Mar 11, 2014 11:35 am

All the info I see on the various Duravent pages refers to heat ratings. In order to have a true All Fuels liner the material would have to be overkill for everything but coal.

I seem to recall reading a post on this forum where someone with a Duravent chimney said they saw perforation in a very short period of time. Scroll down about halfway on this page: http://www.cartech.com/techarticles.aspx?id=1670 for a corrosion resistance graph of the various types of stainless. None of the 400 series rate particularly high.
JohnB
 
Hand Fed Coal Boiler: Hitzer 50-93

Re: MPD location

PostBy: freetown fred On: Tue Mar 11, 2014 11:51 am

dd, I'm still trying to figure out why BO said "change"??
ddahlgren wrote:
JohnB wrote:Note that the majority of the Duravent inner liners are made from 430 stainless which has far lower corrosion resistance then the 316 typically used for stainless chimney liners. Most liner sites recommend 316ti for coal applications over the standard 316 liners. I wouldn't expect the Duravent inner liner to be long lived when used with a coal stove.


How long would you guess? I wonder why Duravent says they are fine with coal? Just temperature rating maybe?
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: MPD location

PostBy: ddahlgren On: Tue Mar 11, 2014 1:39 pm

freetown fred wrote:dd, I'm still trying to figure out why BO said "change


Freetown fred your I don't understand what you are saying in the previous post. "BO"? "change"?
ddahlgren
 
Hand Fed Coal Stove: Crane 404

Re: MPD location

PostBy: Sunny Boy On: Tue Mar 11, 2014 2:08 pm

ddahlgren wrote:
freetown fred wrote:dd, I'm still trying to figure out why BO said "change


Freetown fred your I don't understand what you are saying in the previous post. "BO"? "change"?



"BO". . . . the guy in the White House. . . . you know, the one that promised "change". :roll:

Oh cra& - I just realized I'm starting to understand Fred ! :shock:

Paul
Sunny Boy
 
Hand Fed Coal Boiler: Anthracite Industrial, domestic hot water heater
Baseburners & Antiques: Glenwood range 208, # 6 base heater, 2 Modern Oak 118.
Coal Size/Type: Nuts !
Other Heating: Oil &electric plenum furnace

Re: MPD location

PostBy: ddahlgren On: Tue Mar 11, 2014 2:29 pm

Oh we got change.. Where is Ronny when we need him? How is your health insurance Clinton with 'why does it matter now' the list is endless for the change... sigh...
ddahlgren
 
Hand Fed Coal Stove: Crane 404

Re: MPD location

PostBy: oliver power On: Thu Mar 13, 2014 9:53 am

Lightning wrote:I'll offer something to chew on lol. Y'all are assuming that flue gases are piling up against the manual pipe damper. This idea was brought up on the "Does a manual pipe damper hold heat in a stove" thread.. Personally I think it will make little if any difference where the manual damper is as to how much heat the flue pipe radiates.
Without reading the rest of the replies, I'm with you Lightning. Although, personally, I would have it within arms reach for convenience, and closer to the stove for safety. Speaking of safety; I would think the further towards the chimney you restrict flow, the more chances of fumes coming out additional stove pipe joints. If the damper is close to the stove, chimney can be sucking on the stove pipe joints.
oliver power
 
Stoker Coal Boiler: KEYSTOKER Kaa-2
Hand Fed Coal Stove: Hitzer 50-93 & 30-95, Vigilant (pre-Vigilant-II)
Baseburners & Antiques: MANY (Mostly when burning wood)
Stove/Furnace Make: HITZER / KEYSTOKER
Stove/Furnace Model: 50-93 & 30-95 , Kaa-2

Re: MPD location

PostBy: Sunny Boy On: Thu Mar 13, 2014 10:59 am

oliver power wrote:
Lightning wrote:I'll offer something to chew on lol. Y'all are assuming that flue gases are piling up against the manual pipe damper. This idea was brought up on the "Does a manual pipe damper hold heat in a stove" thread.. Personally I think it will make little if any difference where the manual damper is as to how much heat the flue pipe radiates.
Without reading the rest of the replies, I'm with you Lightning. Although, personally, I would have it within arms reach for convenience, and closer to the stove for safety. Speaking of safety; I would think the further towards the chimney you restrict flow, the more chances of fumes coming out additional stove pipe joints. If the damper is close to the stove, chimney can be sucking on the stove pipe joints.


Since the MPD has holes in it to prevent completely closing off draft to a stove, there should always be some positive pressure outside the pipe joints to push room air into any place the pipes can leak.

So, the only way the fumes can come out a pipe joint is if the draft goes to zero, or a positive mano reading (pressure, not vacuum). And, if that happens, I wouldn't worry about the pipe joints, because your stove will leak more fumes out the open secondary air damper then the joints can. ;)

Paul
Sunny Boy
 
Hand Fed Coal Boiler: Anthracite Industrial, domestic hot water heater
Baseburners & Antiques: Glenwood range 208, # 6 base heater, 2 Modern Oak 118.
Coal Size/Type: Nuts !
Other Heating: Oil &electric plenum furnace

Re: MPD location

PostBy: Sunny Boy On: Thu Mar 13, 2014 11:39 am

Tuesday night, I got to study first hand the loss of heating ability at various parts of my kitchen range, verses at the pipe.

My range is basically a firebox inside a big cast iron box (over 45 square feet) that I can channel the heat to different parts before it gets to the stove pipe. In affect, I can change the size of my range, to three different heat radiating areas, by simply moving two internal dampers.

The other night the girl friend had to work late so I made dinner (and we survived it too ! :D ).

It was still 50 degrees outside and standing at all that hot cast iron up at cooking temps was getting a bit much. The kitchen thermometer said it was in the low 80 degrees.

I always use the IR gun to check the temps of the various parts of the stove top while I'm cooking to see if they are hot enough, or too hot, for what I'm cooking. Much more accurate than using the old time spit-gauge !

To cool the kitchen a bit, I left the stove in indirect mode and reached down and shut the dampers to the water reservoir jacket. That reduces the heat radiating area of the stove's outside surface by about 7-1/2 square feet. With those dampers closed, that sends all the flue gas heat around the oven, then on to the stove pipe instead of splitting it between the oven and the reservoir jacket.


To keep the stove top cooking temps up where I had them, I didn't make any change in the primary air damper, or the MPD setting.

As I was cooking I noticed the stove top temps stayed the same, but within about a half hour the kitchen had dropped back to 75 degrees. I thought maybe it was getting colder outside. Checked the outdoor thermometer and nope, still holding at 50 degrees.

The mano reading went up from .04 to .05 as the draft got a bit stronger from higher heat going to the stove pipe. The pipe temp only went about 10-15 degrees.

So, without changing primary or MPD settings, if adding heat radiating area away from the hottest parts of the stove should take heat from there making those hottest areas colder, why didn't the stove top temps drop ?

And if the heat went up the pipe instead, why, with the loss of that extra 7-1/2 square feet of stove heat radiating area of the water reservoir jacket, did the pipe temp go up such a small amount , yet the kitchen got cooler ?

Paul
Sunny Boy
 
Hand Fed Coal Boiler: Anthracite Industrial, domestic hot water heater
Baseburners & Antiques: Glenwood range 208, # 6 base heater, 2 Modern Oak 118.
Coal Size/Type: Nuts !
Other Heating: Oil &electric plenum furnace

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