Less heat for a given feed rate, same coal

Less heat for a given feed rate, same coal

PostBy: Uglysquirrel On: Sat Nov 30, 2013 8:07 pm

Fourth year with Pocono, absolutely excellent service last three years.

From startup this year, less flame height for same feed rate from last year, same Blaschak entirely dry coal . Replaced back grate gasket though a smoking wood match suggested blow thru on sides of grate bottom box and cast iron grate. Tried to really push down on the grate front to try to ensure a tight fit, this seemed to work for 2-3 weeks though now it seems the flame height is clearly less than last year for the same feed rate and coal as last year. Also really cleaned the combustion fan fins & underside of grate at beginning season. Combustion motor speed seems happy. A window outside is open a bit so not concerned about an vacumn issues in the house. Holes in grate are open, cleaned with a drill.

Interesting, stove side wall temps are down this year as well, 270F temp compared to something like 350 F last year for same feed rate.

In my opinion the combustion box and/or the grate has warped slightly with combustion air leaking. I'm thinking of using some refractory cement to seal the grate to the metal underlying housing. This will pose a removal issue to clan under though it may need to be done.. ;)

Comments ?

Thanks!!

Bruce
Uglysquirrel
 
Stove/Furnace Model: Pocono

Re: Less heat for a given feed rate, same coal

PostBy: Hambden Bob On: Sat Nov 30, 2013 8:28 pm

You got me. I don't own that stove,but dammit,something changed. If you're using last year's dry coal,we know the fuel hasn't changed. It has to be something to do with the draft(Bird or Squirrel's nest built in the off season?) or something in the combustion air travel path. Other than that,I dunno ! :bang:
Hambden Bob
 
Hot Air Coal Stoker Stove: Harman 1998 Magnum Stoker
Coal Size/Type: Rice-A-Roni !

Re: Less heat for a given feed rate, same coal

PostBy: blrman07 On: Sat Nov 30, 2013 9:50 pm

Yepper it sure sounds like you need to seal the grate sides, top and maybe the bottom so the air only goes through the holes.


Rev. Larry
blrman07
 
Hand Fed Coal Boiler: Bucket a Day
Hand Fed Coal Stove: Vigilant Casting 2310
Baseburners & Antiques: rebuilding a 1906 March Brownback Double Heater, using a UMCO 1920's Pot Belly stove in the church
Coal Size/Type: Pea/Nut/Wood in the VC and anything that will fit in the Bucket a Day. It's not fussy.

Visit Leisure Line Stove

Re: Less heat for a given feed rate, same coal

PostBy: Flyer5 On: Sun Dec 01, 2013 12:40 am

Uglysquirrel wrote:Fourth year with Pocono, absolutely excellent service last three years.

From startup this year, less flame height for same feed rate from last year, same Blaschak entirely dry coal . Replaced back grate gasket though a smoking wood match suggested blow thru on sides of grate bottom box and cast iron grate. Tried to really push down on the grate front to try to ensure a tight fit, this seemed to work for 2-3 weeks though now it seems the flame height is clearly less than last year for the same feed rate and coal as last year. Also really cleaned the combustion fan fins & underside of grate at beginning season. Combustion motor speed seems happy. A window outside is open a bit so not concerned about an vacumn issues in the house. Holes in grate are open, cleaned with a drill.

Interesting, stove side wall temps are down this year as well, 270F temp compared to something like 350 F last year for same feed rate.

In my opinion the combustion box and/or the grate has warped slightly with combustion air leaking. I'm thinking of using some refractory cement to seal the grate to the metal underlying housing. This will pose a removal issue to clan under though it may need to be done.. ;)

Comments ?

Thanks!!

Bruce



Are you sure the grate is back all the way and down? Sometimes they need to be persuaded back. You should only feel 1 lip in the front.
Flyer5
 
Stoker Coal Boiler: Leisure Line WL110
Hot Air Coal Stoker Stove: Leisure Line Pioneer

Re: Less heat for a given feed rate, same coal

PostBy: Uglysquirrel On: Sun Dec 01, 2013 9:00 am

Flyer5 wrote:
Are you sure the grate is back all the way and down? Sometimes they need to be persuaded back. You should only feel 1 lip in the front.



Flyer5, good idea....thanks !
Uglysquirrel
 
Stove/Furnace Model: Pocono

Re: Less heat for a given feed rate, same coal

PostBy: titleist1 On: Sun Dec 01, 2013 9:32 am

when cleaning up the grate holes this year i found a couple 'goobers' on the edges of mine that kept them from seating properly. i also thought mine were warped because after setting the one in place the second grate would rock and not sit all the way flush with the other. these 'goobers' were just like the deposits that i cleaned out of the holes. i scraped them off and everything set nice and flush with no rocking.
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: Less heat for a given feed rate, same coal

PostBy: Uglysquirrel On: Mon Dec 02, 2013 9:06 pm

Flyer5 wrote:
Uglysquirrel wrote:Fourth year with Pocono, absolutely excellent service last three years.

From startup this year, less flame height for same feed rate from last year, same Blaschak entirely dry coal . Replaced back grate gasket though a smoking wood match suggested blow thru on sides of grate bottom box and cast iron grate. Tried to really push down on the grate front to try to ensure a tight fit, this seemed to work for 2-3 weeks though now it seems the flame height is clearly less than last year for the same feed rate and coal as last year. Also really cleaned the combustion fan fins & underside of grate at beginning season. Combustion motor speed seems happy. A window outside is open a bit so not concerned about an vacumn issues in the house. Holes in grate are open, cleaned with a drill.

Interesting, stove side wall temps are down this year as well, 270F temp compared to something like 350 F last year for same feed rate.

In my opinion the combustion box and/or the grate has warped slightly with combustion air leaking. I'm thinking of using some refractory cement to seal the grate to the metal underlying housing. This will pose a removal issue to clan under though it may need to be done.. ;)

Comments ?

Thanks!!

Bruce



Are you sure the grate is back all the way and down? Sometimes they need to be persuaded back. You should only feel 1 lip in the front.



Backed off the feed rate, put on my leather gloves and used an adjustable c-clamp to lightly compress the upper front grate edge against the lower sheet metal box edge while still burning. The grate did move a scoshe down. Flame seems a scoshe higher . :D

Whats a "scoshe"?
Uglysquirrel
 
Stove/Furnace Model: Pocono

Re: Less heat for a given feed rate, same coal

PostBy: SMITTY On: Mon Dec 02, 2013 9:23 pm

It is what it is. :D

That's a New England word. ;)
SMITTY
 
Stoker Coal Boiler: Patriot Coal - custom built by Jim Dorsey
Hand Fed Coal Stove: Harman Mark III (not currently in use)
Coal Size/Type: Rice / Blaschak anthracite
Other Heating: Oil fired Burnham boiler

Re: Less heat for a given feed rate, same coal

PostBy: Matthaus On: Sat Dec 07, 2013 3:17 pm

I'm adding a couple points to consider in this discussion:
Any time there is a change in stove behavior don't forget the other side of the equation, the chimney or power vent. For a given CFM combustion air/coal btu value burning there also has to be a corresponding volume and pressure to effectively take the products of combustion and expel it outside. If the draft is low (still negative but say -.02"WC instead of -.04"WC) it can affect the burn rate and size of the flame. We have seen customers prove this by keeping their stove stove lit solely with the power vent after the combustion fan failed by cranking it up all the way and holding the baro shut (don't try this at home kids, guaranteed hopper fire!). Another possibility is some kind of restriction not allowing full flue gas flow (such as fly ash built up in an area not cleaned or a birds nest), this can affect the size of the flames and burn rate of the coal.
Matthaus
 
Stoker Coal Boiler: Leisure Line WL110 Dual Fuel, natural gas
Hot Air Coal Stoker Stove: Leisure Line Lil' Heater (rental house)
Coal Size/Type: Rice and Buckwheat Anthracite

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