Comparing Temps Between Flue Pipe and Stove Body

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: titleist1 On: Fri Nov 08, 2013 1:22 pm

lightning, one suggestion i'd make on your mano is to put a short piece of tubing on the other port looped toward the floor to keep any dust or dirt from getting in that open port. probably not a big issue, but just something that was suggested to me way back when and i thought i'd pass it along for others to consider.
titleist1
 
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: Stanb999 On: Fri Nov 08, 2013 1:30 pm

Lightning wrote:Oh yeah lol right. It's hooked up backwards to read the negative value on the positive side of the scale. Sorry :lol:



He was thinking your stove blew, when really it's your chimney sucking. :lol:
Stanb999
 
Stove/Furnace Make: Harmon
Stove/Furnace Model: Mark II

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: Lightning On: Fri Nov 08, 2013 3:13 pm

Stanb999 wrote:
Lightning wrote:Oh yeah lol right. It's hooked up backwards to read the negative value on the positive side of the scale. Sorry :lol:



He was thinking your stove blew, when really it's your chimney sucking. :lol:


Right hahaha, I didn't name her Ashley cuz she blows but because she's hot. :lol:
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

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Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: Lightning On: Fri Nov 08, 2013 3:16 pm

titleist1 wrote:lightning, one suggestion i'd make on your mano is to put a short piece of tubing on the other port looped toward the floor to keep any dust or dirt from getting in that open port. probably not a big issue, but just something that was suggested to me way back when and i thought i'd pass it along for others to consider.


Yes sir, I actually folded a little piece of news paper over the open port for any dust to settle on. It's not tight against the port so it can't alter the reading. Your suggestion is excellent too :D
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: titleist1 On: Fri Nov 08, 2013 3:32 pm

yes, i noticed the paper in the pic when i zoomed in that is what made me think of passing along the tubing suggestion.

by the way, i figured out how to get you the info on the mano reading at different baro opening points you were asking about. i must have had brain lock when trying to think about it the first time through. what i'll do is wait to see the baro steadily open about halfway (and other points) and then manually close it while noting the new reading on the mano with the baro closed. i will find the other thread and add the data in case it helps.
titleist1
 
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: ddahlgren On: Fri Nov 08, 2013 3:47 pm

Lightning wrote:
titleist1 wrote:lightning, one suggestion i'd make on your mano is to put a short piece of tubing on the other port looped toward the floor to keep any dust or dirt from getting in that open port. probably not a big issue, but just something that was suggested to me way back when and i thought i'd pass it along for others to consider.


Yes sir, I actually folded a little piece of news paper over the open port for any dust to settle on. It's not tight against the port so it can't alter the reading. Your suggestion is excellent too :D


A small piece of foam makes a great filter though keep it away from the heat and keeps all the trash.
Whenever I have to tap into something that is hotter than the melting temp of the rubber or plastic tubing connected to the sensor I always uses a couple of feet of copper tubing wound in a coil to cool the end of it and not melt the plastic or rubber tubing. I know it works with 1800 to 2000F temperatures quite well on the exhaust of a turbocharged race engine measuring exhaust back pressure.
ddahlgren
 
Hand Fed Coal Stove: Crane 404

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: Lightning On: Fri Nov 08, 2013 10:27 pm

titleist1 wrote:by the way, i figured out how to get you the info on the mano reading at different baro opening points you were asking about. i must have had brain lock when trying to think about it the first time through. what i'll do is wait to see the baro steadily open about halfway (and other points) and then manually close it while noting the new reading on the mano with the baro closed. i will find the other thread and add the data in case it helps.


Cool Thank you! Basically, I was trying to relate mano readings with how far open the door was. I should have gotton a reading with the baro held closed too but didn't think of it at the time :D
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: Lightning On: Sun Jan 04, 2015 8:48 pm

Hi Fellas.. I'd like to resurrect this thread for opinions on stove vs pipe temp and what they imply or if they are really very valid at all.. :shock:

Its just that there are SOOOO many variables that contribute to the spread between the stove and pipe.

Lets start with location. My pipe can be 200 degrees 12 inches from breech and 2 feet further up the pipe I can lay my hand on it. Then at the thimble its hardly luke warm. Then there is the location on the pipe itself. The top side of a horizontal pipe can be hot while the underside is much cooler. How does that work for a vertical pipe?

Then there is the burn rate issue. At lower burn rates I see a closer gap between stove and pipe. Is this because the top of the coal bed is cool and not producing radiant heat? At higher burn rates I see a more dramatic spread. Is this because the top of the coal bed is glowing and throwing massive amounts of radiant heat that the steel is absorbing?

And how about that secondary air? When I close my secondary air, the pipe cools.. Open secondary air and the pipe temp rises.. but, in both cases the stove temp stays the same.. Is this because more heated air MASS is running across the inside of the pipe surface by opening the secondaries?

And what about heat loss of the pipe itself? Last year I held my probe against the pipe with magnets. I could blow on it to cool it down. This year I secured the probe under a thin layer of insulation and blasted foil tape over it. Since the pipe isn't exposed where the probe is, it sees a higher temperature.

With all these variables and inconsistencies from one set up to the next, how can we justify any amount of efficiency based on these numbers?

Any comments are appreciated..
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: lsayre On: Sun Jan 04, 2015 8:53 pm

Lightning wrote:With all these variables and inconsistencies from one set up to the next, how can we justify any amount of efficiency based on these numbers?

Any comments are appreciated..


You are of course quite correct. We can't make heads or tails out of anything when there are no standards or controls being adhered to.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Stockton Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: franco b On: Sun Jan 04, 2015 9:00 pm

Without a fixed method of measurement , you are right that most value is lost.

Stack temp. ideally should be measured within a foot of the stove breech and with a probe into the pipe. Even surface temp. would be useful if everyone measured at that point, but many measure at the thimble or after a baro and the measurement is useless.
franco b
 
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: windyhill4.2 On: Sun Jan 04, 2015 9:18 pm

380* stove top,top end of the elbow on stove is 180*,right b4 the elbow b4 the thimble is 118*,the thimble end of that elbow is 105*. If these measurements turn out to be invalid because they have no scientific merit,how about this measurement............. We are WARM,does that one count ? :)
windyhill4.2
 
Stoker Coal Boiler: 1960 EFM520 installed in truck box
Hand Fed Coal Stove: Crane 404 with variable blower
Coal Size/Type: 404-nut, 520 rice ,anthracite for both

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: dlj On: Sun Jan 04, 2015 10:32 pm

lsayre wrote:
Lightning wrote:With all these variables and inconsistencies from one set up to the next, how can we justify any amount of efficiency based on these numbers?

Any comments are appreciated..


You are of course quite correct. We can't make heads or tails out of anything when there are no standards or controls being adhered to.


It's my understanding that this is not a field that has been completely defined yet at any level. Methods of measuring temperature and constituents within the exhaust/chimneys are still being developed. I believe the current methods being pursued in research are using LASERs to shoot through the exhaust stream enabling the measurement of the complex temperature profiles within the exhaust stream, volume, flow rates, as well as measuring the various constituents within the exhaust gases.

This all being said, knowing that your stove pipe has much less going up it in heat, per a surface measurement, can give a nice warm fuzzy feeling... :D

dj
dlj
 
Hand Fed Coal Stove: Vermont Castings Resolute
Baseburners & Antiques: Glenwood Baseheater #6
Coal Size/Type: Stove coal
Other Heating: Oil Furnace, electric space heaters

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: Lightning On: Sun Jan 04, 2015 10:49 pm

dlj wrote:This all being said, knowing that your stove pipe has much less going up it in heat, per a surface measurement, can give a nice warm fuzzy feeling...
Yes, I suppose it does.. 8-)
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: 2001Sierra On: Sun Jan 04, 2015 11:45 pm

How you measure does matter. Here are my stove pipe readings. The large white gauge has a probe into the flue, about 2 inches.
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2001Sierra
 
Hot Air Coal Stoker Stove: Keystoker 90 Chimney vent
Coal Size/Type: Rice
Other Heating: Buderus Oil Boiler 3115-34
Stove/Furnace Model: Keystoker 90 Chimney Vent

Re: Comparing Temps Between Flue Pipe and Stove Body

PostBy: titleist1 On: Mon Jan 05, 2015 12:13 am

I don't use the comparison of the two temps to make any claims on efficiency percentages. I don't really even look to them to be extremely accurate temperature readings for all the reasons already stated.

What I do expect is that the flue & stove body gauges are repeatable in the measurement so they are useful when viewed individually from time to time or compared to each other. I am used to looking at the temp probe on the flue pipe and seeing about 130* when idling and 275* when at full burn for at least 30 minutes. I am used to seeing about 200* on the stove body when mostly idling and 600* when at full burn for at least 30 minutes measured with an IR gauge at the same point each time.

Because of that I can tell when I first look in the morning if it has been firing or idling for a while just by looking at the flue temp. And I can tell if something may be wrong if the temp spreads are not their usual values. For instance, if the flue temp looks too high compared to the stove body temp i look at the manometer & check the baro to make sure it is open as far as it should be since it seems I am sending heat up the chimney. Last year a couple day long chronically low stove temp led me to notice a smaller fire than normal (glass is frosted too badly to see flames clearly) which led me to find the combustion fan not seated properly and only supplying about 2/3's the normal air.

So other than giving somebody new a little reassurance that their temps are 'in the ballpark' i view the temps i measure as useful to myself only.
titleist1
 
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite

Visit Hitzer Stoves