Manual pipe dampers .. how, why, when

Re: Manual pipe dampers .. how, why, when

PostBy: Lightning On: Wed Dec 11, 2013 10:24 pm

dbsuz05 wrote:My experience with MDP's so far.... closing it cools cools er' down and opening heats er' up. Check damper door open on windy days and closed on the calm.


Good point.. Many people have the misconception that a MPD "holds the heat in the stove"... :)
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Manual pipe dampers .. how, why, when

PostBy: Bruce M On: Wed Dec 11, 2013 11:51 pm

dbsuz05 wrote:My experience with MDP's so far.... closing it cools cools er' down and opening heats er' up. Check damper door open on windy days and closed on the calm.

I have had the exact opposite experience with my stove, could it be when you open your damper it allows more air to be pulled through the stove thus firing the stove hotter.
Bruce M
 
Hand Fed Coal Stove: DS Machine 1627 basement stove

Re: Manual pipe dampers .. how, why, when

PostBy: freetown fred On: Wed Dec 11, 2013 11:53 pm

I don't think that's a misconception at all Lee. Think about it. I don't know much about physics--but if I did, I'd have to say, it's just physics. toothy -- On warm days, I keep my MPD open & it lets heat out of the stove--YES--heat RISES--during the cold months, I keep it closed to PREVENT the heat from rising & escaping from the stove body. Just sayin.
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

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Re: Manual pipe dampers .. how, why, when

PostBy: Carbon12 On: Thu Dec 12, 2013 12:16 am

Eh,...ah,....my brain hurts Mr. Gumby. I did not know MPD were supposed to control burn rate. I still might not know that.
Carbon12
 
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

Re: Manual pipe dampers .. how, why, when

PostBy: Lightning On: Thu Dec 12, 2013 4:01 am

freetown fred wrote:I don't think that's a misconception at all Lee. Think about it. I don't know much about physics--but if I did, I'd have to say, it's just physics. toothy -- On warm days, I keep my MPD open & it lets heat out of the stove--YES--heat RISES--during the cold months, I keep it closed to PREVENT the heat from rising & escaping from the stove body. Just sayin.


I know right? It goes against the grain of the normal thinking.. And I bet it will open a whole new big yucky slimy can of worms.. :lol: When I close my manual damper, I see a number of things happen. Starting with, the manometer showing a weaker draft. Then shortly after, the flue pipe temp starts to drop, the over the load door temp starts to drop and the burn rate starts to drop. Nowhere do I ever observe an increase in heat anywhere when I close the MPD. So I'm not quite on board with that. I'm sure its a matter of perspective :)
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Manual pipe dampers .. how, why, when

PostBy: freetown fred On: Thu Dec 12, 2013 6:34 am

Lee, I would suspect that possibly you need some more under fire air which your mano would jump some with the MPD open, but settle back down when closed--just thinkin out loud my friend--what you're describing just don't sound kosher--Oh yeah, this old farmer knows a little Yiddish--I used to be a pretty worldly kinda guy! :clap: toothy
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: Manual pipe dampers .. how, why, when

PostBy: Rob R. On: Thu Dec 12, 2013 7:16 am

Bruce M wrote:could it be when you open your damper it allows more air to be pulled through the stove thus firing the stove hotter.


Yes.
Rob R.
 
Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
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Re: Manual pipe dampers .. how, why, when

PostBy: Lightning On: Thu Dec 12, 2013 8:51 am

Rob R. wrote:
Bruce M wrote:could it be when you open your damper it allows more air to be pulled through the stove thus firing the stove hotter.


Yes.


I also agree.
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Manual pipe dampers .. how, why, when

PostBy: rberq On: Thu Dec 12, 2013 9:26 am

Lightning wrote:
dbsuz05 wrote:My experience with MDPs so far.... closing it cools cools er' down and opening heats er' up. Check damper door open on windy days and closed on the calm.

Good point.. Many people have the misconception that a MPD "holds the heat in the stove"... :)

Oh, good. I thought it was just me. I installed a MPD this year for the first time (along with the baro), and the MPD just cools the stove. I have stopped using the MPD.
rberq
 
Hand Fed Coal Stove: DS Machine 1300
Coal Size/Type: Nut -- Kimmel/Blaschak/Reading
Other Heating: Oil hot water radiators, propane

Re: Manual pipe dampers .. how, why, when

PostBy: KLook On: Thu Dec 12, 2013 9:35 am

Carbon+O=Oxidation=Heat. MPD + < O= < Oxidation= < Heat

Kevin
KLook
 
Stoker Coal Boiler: Harman VF 3000
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Stove/Furnace Make: Harman (Back In Maine)
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Re: Manual pipe dampers .. how, why, when

PostBy: Lightning On: Thu Dec 12, 2013 3:58 pm

Here's a thread I started about the last few posts if anyone is interested

Manual Pipe Dampers - A Matter of Perspective
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Manual pipe dampers .. how, why, when

PostBy: Sunny Boy On: Thu Dec 12, 2013 4:31 pm

Lightning wrote:
dbsuz05 wrote:My experience with MDP's so far.... closing it cools cools er' down and opening heats er' up. Check damper door open on windy days and closed on the calm.


Good point.. Many people have the misconception that a MPD "holds the heat in the stove"... :)


I don't think it is that black and white if it could be measured accurately. It think it does matter how much the MPD is closed for a particular stove's draft, etc. And that the MPD can, "hold the heat in", by helping to fine tune the speed that the hot gasses move through the stove to maximize heat transfer out of the stove and the stove pipe.

And, remember, not all MPD plates have the same size and number of holes in them. What works for one may not work the same way for others. That doesn't mean the hold heat in is a misconception, but very likely, just misapplied.

I've been checking this with actual surface temperature measurements with an IR gun and a manometer in the stack about a foot below the MPD.

These readings are all being done keeping the primary air opening always the same - set to .045 gap with a feeler gauge, and only take when the range is in indirect mode, to be as consistent as I can and remove those as variables. The only thing that gets changed between heat and mano readings is the angle of the MPD.

So far the numbers are showing a narrow range of MPD angle that gets and keeps the hottest part of my stove hotter, while the stack temp will drop some.

With the MPD fully open to 90 degrees the hot end stays in the low to mid 600 degree range. Mano stays about .07-.08.

With the MPD set to about 35 degrees, the hot end plates get up in the low to mid 700 degrees and the stack temps drop 20-30 degrees. And the mano drops to .04.

If I close the MPD just a bit more than that, the hot end plates will very slowly start to get cooler and so will the stack temp.

If I open it slightly more then that 30-35 degree angle say to 45 degrees, the stack temps go up, but the hot end of the stove temps slowly drop back into that 600 degree range.

I'm not saying my tests are proof that it will work with every coal stove, . . I'm just showing that with actual, accurate temperature reading that it isn't a misconception for all coal stoves.

The "hold heat in" saying may be an old wives tail because it may only work for the old style stoves with the longer internal passageways that kitchen ranges, base burners, and back-pipe parlor stoves have.

Paul
Sunny Boy
 
Hand Fed Coal Boiler: Anthracite Industrial, domestic hot water heater
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Re: Manual pipe dampers .. how, why, when

PostBy: freetown fred On: Thu Dec 12, 2013 6:01 pm

SB, you really do different angles with your MPD? I mean like other then half closed or totally closed? I remember my Father tellin me once on the farm in Bucks Co. Pa--" ya know, the more complicated/ complex the gadgets, the more complicated/ complex the theories--just sayin ;)
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: Manual pipe dampers .. how, why, when

PostBy: warminmn On: Thu Dec 12, 2013 6:52 pm

I dont know who's right or wrong :lol:

With my surdiac I look at the forcast in the morning before I go to work. The more wind they predict, the more I close my damper before I leave. Yes, i do think it slows the fire down. Ive learned about how to set it to have about the same fire 10-12 hours later using the damper. My air intake is usually the same when I leave. I rarely have it closed more than maybe 75 percent.
warminmn
 
Hand Fed Coal Stove: Chubby Junior, Efel Nestor Martin
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Re: Manual pipe dampers .. how, why, when

PostBy: Sunny Boy On: Thu Dec 12, 2013 7:14 pm

freetown fred wrote:SB, you really do different angles with your MPD? I mean like other then half closed or totally closed? I remember my Father tellin me once on the farm in Bucks Co. Pa--" ya know, the more complicated/ complex the gadgets, the more complicated/ complex the theories--just sayin ;)



Just for testing purposes, Fred.

Normally, the MPD is fully open during loading and cooking, about 35 degrees during the day for just heating, and fully closed at night.

Yup, I think your Dad was right. I'm a believer in K.I.S.S too. However, I'm also very curious about how things work. And, how these old sayings get started. I like to see if there is any truth to them, . . so then I run tests.

Maybe it was that I watched too many Mr. Wizard shows on TV as a kid. :D

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 !
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