Magnum stoker settings for the control box

PostBy: lime4x4 On: Thu Oct 26, 2006 7:09 pm

i've found that when using my way i can burn between 1.75 to 2.5 hoppers full of coal before empting the ash pan
lime4x4
 

Re: Magnum stoker settings, first year with new stove.

PostBy: s7mar7in On: Wed Dec 31, 2008 1:49 am

Hello All,
Could I please add a related question.
Q: Does reducing the push-block stroke to less the 2 dots create a "tight fit" for coal exiting the hopper?

Harman Magnum Stoker: 2-10-5 with combustion fan restrictor plate at 30% "Open".

Many Thanks for any advice,
John
s7mar7in
 
Stove/Furnace Make: Harman
Stove/Furnace Model: Magnum Stoker

Re: Magnum stoker settings for the control box

PostBy: coalkirk On: Wed Dec 31, 2008 8:32 am

Yes. If you operate your stove with the hopper emtpy once, look down in the hopper. The pusher block retracts and that allows coal to fall down in front of it. The less it retracts, the smaller the area for coal to fall and fill. It would produce a low burn. If that's doing the job, then thats fine.
coalkirk
 
Stoker Coal Boiler: Harman VF3000
Coal Size/Type: antrhcite/rice coal

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Re: Magnum stoker settings for the control box

PostBy: s7mar7in On: Wed Dec 31, 2008 2:05 pm

Thank you for a perfect answer,
I am not as familiar with the stoker as I will be after the end of winter maintenance.
If this were my stove to design, I think an ample opening at all feed settings would be the goal.
With larger and smaller pieces of coal in each hand-full, I worry that a "One Dot" stroke setting may fail to feed coal at times.
...in fact, that has been my observation in my limited experience.
Warm Regards,
John
s7mar7in
 
Stove/Furnace Make: Harman
Stove/Furnace Model: Magnum Stoker

Re: Magnum stoker settings for the control box

PostBy: coalkirk On: Wed Dec 31, 2008 8:31 pm

One dot is a really low setting but it will still feed coal. The stoker motor is very powerful and if a piece of coal only goes partially into the feed area, the pusher block will break it off. That's where alot of the dust comes from that accumulates in the pull out tray under the stoker. My boiler has the same stoker and I run it at about 3 - 3 1/2 dots.
coalkirk
 
Stoker Coal Boiler: Harman VF3000
Coal Size/Type: antrhcite/rice coal

Re: Magnum stoker settings for the control box

PostBy: s7mar7in On: Fri Jan 02, 2009 9:17 pm

Hello,
Let us take the next step in this operator lesson.
Our stove is set as follows;
Dwell timer-10 minutes
Run timer-2 minutes
Combustion Blower Inlet- Throttled to 30%
Distribution fan delay-3 minutes
Coal Stoker Stroke-2 dots / (.250")
Outside Temperature- 0 degrees F to 35 degrees F
"LIFE IS GOOD AND THE THERMOSTAT IS USUALLY SATISFIED"
( :idea: In future we will call this setting: 2-10-3-RP;30-CSS;2)

Now then: As the outside temperature drops below 0 degrees F, what is the proper change to the "maintenance mode settings" or do we allow the stove to run as needed to satisfy the thermostat and leave the settings alone?
(I would expect a single adjustment to either run timer or stroke would put the stove into "cold weather maintenance mode")

Warm Regards from New Hampshire, (-10 F and windy)
John
s7mar7in
 
Stove/Furnace Make: Harman
Stove/Furnace Model: Magnum Stoker

Re: Magnum stoker settings for the control box

PostBy: ginski On: Fri Jan 02, 2009 10:05 pm

hi john,

i've had my magnum for three seasons now & keep my control box settings at 4-12-15....15 being that the hot air distribution blower is always on.

the combustion blower is plugged into a separate outlet (not the control box) so it is always running.

my damper on the combustion blower has always been set to 1/2 open.

my feed rate setting is really the only item i change...1dot to 1-1.5 dots (in spring & fall) to 2 dots to 3 dots in winter, depending on how cold it is.

tom
ginski
 
Stove/Furnace Make: harman
Stove/Furnace Model: magnum stoker

Re: Magnum stoker settings for the control box

PostBy: Dutchman On: Sat Jan 03, 2009 1:28 am

we allow the stove to run as needed to satisfy the thermostat and leave the settings alone


Hi John,

Yes, that is exactly what I do. The timer settings are, by my way of figuring, the way to set how much heat the stove will make in "pilot" or "standby" mode, ie the minimum size of the fire at all times. The stoker setting (length or dots) controls only how much coal feeds into the fire when the stoker motor runs; for the last few years, once I assemble and set the pusher, it won't get fiddled with again at all 'till the end of the season.

That being said, I adjusted the pusher stroke in the fall so as to keep an inch or two of ash at the end of the grates whenever the Mag is running full burn, and my timers I adjust periodically (for a very small fire in the early and late season, and for a somewhat larger fire during winter). Right now I'm at 4 on, 13 off to maintain a 275 minimum surface temp for now.

Then, when the thermostat calls for heat, the controller overrides the timer so that the stoker will run constantly and build a full fire until the thermostat is satisfied. I use an off-the-shelf digital program job from the local hardware store and it's great in my book. With the screwy weather we've been having in PA this year (50 degrees one day, -15 wind chill the next) the thermostat has kept the house right on temp better than I ever could if I was adjusting timers & settings all the time.

I also run the combustion blower full-time, the burn quality is better, & I've installed a rheostat to control the blower output instead of using the restrictor plate. Hope this helps! :)
Dutchman
 
Hot Air Coal Stoker Stove: Harman Magnum
Coal Size/Type: rice/anthracite

Re: Magnum stoker settings for the control box

PostBy: s7mar7in On: Sat Jan 03, 2009 5:53 am

Thank You for sharing your experience.
I think the question remains though... ;)

Let's say the night is getting cold and the stove is firing to keep the thermostat satisfied;
Q: How long do we want the stove to fire before it returns to pilot mode?

Q: When we move into the coldest weeks of the winter, do I want to maximize the stroke, (first) or increase the "On Timer" by a minute?

Note: It is clear that we want the air to lead the fuel and will want to modify the combustion fan control somehow.

But we are gaining, and I can't tell you how much your help is appreciated.

Warm Regards,

John
s7mar7in
 
Stove/Furnace Make: Harman
Stove/Furnace Model: Magnum Stoker

Re: Magnum stoker settings for the control box

PostBy: coalkirk On: Sat Jan 03, 2009 11:34 pm

I'll take a stab at these.

s7mar7in wrote:Let's say the night is getting cold and the stove is firing to keep the thermostat satisfied;
Q: How long do we want the stove to fire before it returns to pilot mode?

I'd say you want the stove to fire until the thermostat is satisfied. Pilot mode is only to keep the coal burning between thermostat demand cycles.
Q: When we move into the coldest weeks of the winter, do I want to maximize the stroke, (first) or increase the "On Timer" by a minute?

Increase the stroke which will feed more coal. Changing the on setting only affects pilot mode.

Note: It is clear that we want the air to lead the fuel and will want to modify the combustion fan control somehow.
coalkirk
 
Stoker Coal Boiler: Harman VF3000
Coal Size/Type: antrhcite/rice coal

Re: Magnum stoker settings for the control box

PostBy: s7mar7in On: Sun Jan 04, 2009 5:18 am

Hello and Thank You Again,
I feel like the college freshman who is too full of questions in the first year...but I am starting to pull the big pieces together now.
(And as was said in the beginning, we knew this would be a year for learning)

The pilot mode settings seem to be extremely reliable and yet they are also quite efficient.
I like to think of the percent firing time as one view of economizing on fuel.
I.E. (2) minutes run / (10) minutes dwell = coal feeder "ON" two minutes out of every twelve minutes = coal feeder "ON" only ten minutes/hour :D

As we get into the colder weeks of the season, I will increase the stroke enough that the stove is not firing "LEAN" but may then need to extend the dwell timer to get the "LOW FIRE" that is desired in pilot mode. (Sorry, lots of thinking out-loud)

Warm Regards,
John
s7mar7in
 
Stove/Furnace Make: Harman
Stove/Furnace Model: Magnum Stoker

Re: Magnum stoker settings for the control box

PostBy: coalkirk On: Sun Jan 04, 2009 11:58 am

John the bottom line is whatever is working for you is good as every installation is somewhat unique. Whatever adjustments you make, give them time to take effect and note the results as coal responds much more slowly to changes in feed rate, air and timer settings than other fuels. You've got a great stove that should serve you well for a long time to come. Don't be concerned about being too full of questions. Most of us were at one time. And like most things in life, when you think you know all there is to know, you are about to learn a lesson. ;)
coalkirk
 
Stoker Coal Boiler: Harman VF3000
Coal Size/Type: antrhcite/rice coal

Re: Magnum stoker settings for the control box

PostBy: jws3 On: Sun Jan 11, 2009 11:55 am

To those of you who run the combustion blower all the time, is the feed motor running at the same time, or just when pilot mode or the thermostat calls for it?
jws3
 
Stove/Furnace Make: Harmon
Stove/Furnace Model: Magnum Stoker

Re: Magnum stoker settings for the control box

PostBy: Horace On: Sun Jan 11, 2009 8:27 pm

jws3 wrote:To those of you who run the combustion blower all the time, is the feed motor running at the same time, or just when pilot mode or the thermostat calls for it?


Only when called for by the t-stat or by the control box ('On' timer) when at idle.
Horace
 
Hot Air Coal Stoker Stove: Harman ST8-VF8 / Frankenstove

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