Harman Mag Stoker with Coal-Trol report

Harman Mag Stoker with Coal-Trol report

PostBy: pvolcko On: Tue Dec 05, 2006 4:30 pm

We've had the Coal-Trol Digital being tested on a Harman Mag Stoker for the last 2-3 weeks now and it is time for an update.

The tester reports that it is working great. He's using a min setting of 6 and a max of 99 after some experimentation with the manual adjustment controls. We'll be getting pictures sent to us soon. When we get them we'll be scanning them and posting them on our site, and we'll provide links to there on this thread.

The testing has covered mid 60's to mid 20's weather and it has been used as the primary heat source during this time.

So we're 100% comfortable now saying that we work with Harman Mag Stokers. For those of you who have been waiting for this report, please feel free to ask questions or go ahead and order. :)
pvolcko
 

PostBy: BurninCoalInRI On: Thu Dec 07, 2006 9:35 pm

why would i want to spend hundreds of dollars upgrading the controls when they already run the stove? yes this is a serious question, ;) what does coal-trol do better than the oem controller box?
BurninCoalInRI
 

PostBy: pvolcko On: Fri Dec 08, 2006 2:03 am

It's a fair question.

Many people are not satisfied with their current controls. Manual controls can require frequent adjustment. With practice and experience one gets better at using them, but generally you end up accepting a certain level of over or under heating. Timer boxes and rheostats can simplify things, but you still end up having to chase the outdoor temperature changes with adjustments and things can be quite a bit off if you leave the house for the day or when you wake up in the morning.

Some people have thermostat controls that they bought with their stove. Typcially it is a bell thermostat or a more crude thermostat box, either of which works in conjunction with a timer that provides idle feed setting, and maybe it also provide a full feed setting (or this is set with the manual controls). These setups often result in widely fluctuating temperature control, though. If it is set to 70, for instance, the actual temperature in the room can swing up to 5 or more degrees above and below that setting.

This happens and the effect is strengthened by a number of factors, but the root cause is that coal fuel takes a long time (compared to electric, gas, oil, or hot water heating systems) to generate the heat being called for by the thermostat. This delay results in under and over shoots in the temperature of the space when controlled by a traditional thermostat.

Manual and timer/dial controls often result in even worse fluctuations unless they are at the hands of a seasoned coal stove owner.

And these fluctuations don't only result in discomfort, they result in wasted fuel as the stove over heats the space or has to overcome the low of a temperature dip.

The Coal-Trol Digital control systems work on a different principle than traditional thermostats, which allow them to feed only enough coal as is needed to maintain the desired temperature. It will maintain that temperature setting to within 1 degree of the setpoint, and while providing that level of comfort and ease of use you will be saving coal (at least 11%, usually more) by having eliminated those large temperature fluctuations. Of course, when a programmed or manual temperature setpoint change occurs it takes some time for the temperature to adjust, just as with any thermostat, but once at the desired temperature we maintain it within that 1 degree range.

We also offer additional features depending on the model one wants to buy, all of which are detailed at our website at http://www.coaltroldigital.com.

Lastly, we're actively working on an automatic ignition module that will work with our systems. In addition to making it very easy (and clean) to start the stove, it will extend the practical usefulness of the stove further into the transition seasons of spring and fall.

So that's my shpiel.

As you say, if you're happy with what you have then there may not be enough reason for you to try a Coal-Trol Digital system out. But if you're seeing the kind of temperature fluctuations I described or after looking at our website and searching the forum's prior discussions on the Coal-Trol you see value, we encourage you and others to ask questions and hopefully order a system.

We offer a 3 year warrantee and a 30 day money back guarantee and multiple avenues (email, these forums, phone call, etc.) for customer support. System prices are from $250 to $450.

Thanks for your question. Ask as many as you like, that's what we're here for. :)
pvolcko
 

PostBy: BurninCoalInRI On: Fri Dec 08, 2006 1:19 pm

thanks for the answers. im not sure my own system is doing any chasing yet, it seems to run pretty steady in the low 70's. maybe thats ebcause the harman is in the basement and the tstat is upstairs (i use the air duct), so after it calls for heat and gets satisfied, the air stops 1 min later.

but the coal trol intrigues me just the same, and here's a couple more questions/suggestions.

on the website, there are 4 models. i didnt find a feature comparison chart, that would help and especially if it also included a harman-type standard controller.

at any rate, while the site is well laid out and i do get the general idea it provides bvetter heat control, i dont know all the differences between the 4 models, or even which one(s) would or would not work on my harman, for example.

also, do the coal trol units have rheostat control for my 3 motors, and if so, how can we be sure that my 3 motors are suitable to be rheostat controlled?

also, if the feed motor is rheostat controlled, does it more easily jam at lower voltages?

also, this is a very cool product!

thanks!
BurninCoalInRI
 

PostBy: pvolcko On: Fri Dec 08, 2006 1:45 pm

on the website, there are 4 models. i didnt find a feature comparison chart, that would help and especially if it also included a harman-type standard controller.

Here are the only comparison charts we have currently.
http://www.automationcorrect.com/Thermostats.htm
http://www.automationcorrect.com/ControlModules.htm
I agree, these could be more prominent on the site and the idea of including a standard thermostat control system is interesting.

or even which one(s) would or would not work on my harman

They all would work. All of our systems will work on any stoker stove, but there are feature differences that distinguish them. Built in Igniter support, integrated power vent connections, forced air furnace fan control contact option, etc. on the control modules. Different numebr of setpoints, manual fan control, etc. on the thermostats.

also, do the coal trol units have rheostat control for my 3 motors, and if so, how can we be sure that my 3 motors are suitable to be rheostat controlled? also, if the feed motor is rheostat controlled, does it more easily jam at lower voltages?


The convection fan output is a speed control. It isn't a traditional rheostat, but it does provide variable voltage output. The stoker is either on/off or speed controlled (depending on the triburn setting in the thermostat). In on/off mode the time proportion of on vs. off is varied by the thermostat to achieve the variable heat output. Combustion is either on or off, not time proportioned or speed controlled at all.

When we are speed controlling the stoker output our lowest speed is 50% (we always time proportion below that rate), which is more than enough to keep them turning in almost all circumstances. Chances are if we get jammed at low speed it would have jammed at higher speed too.

also, this is a very cool product!


Thanks! :)
pvolcko
 

PostBy: AL-53 On: Fri Dec 08, 2006 7:10 pm

How do you speed control the feed motor...it is a capacitor start and shaded pole motor..I have inquired about this many times with suppliers and engineeers and was told only true way was a frequency controller....or a controller specific to that type motor....I have tried a few types of speed contollers and it would not reduce the speed at all...due to it being a shaded pole motor...

Do you just pulsate a feed to the motor..letting it feed and stop in bursts...


One of the engineers made a box for me try out...it is not a speed controller but a cycle timer..where i can adjust the cycles of the feed motor to temps needed..so far it has been working good..giving me the heat and also reducing coal usage..utilizing a complete burn cycle..


I am still very interested in the Coal trol...and before any decisions will watch the progress over the winter....please keep us updated...

Al
AL-53
 

PostBy: pvolcko On: Mon Dec 11, 2006 11:12 pm

Hi Al, as far as I know on the Harman's they are 2 motor stoker designs so there is no speed controlling of either motor, just time proportioning.

And for everyone:

We've gotten a more detailed report back from the guy testing our control out on the Harman stove, Denny Hess. We've posted it and blurb about it on our site on the main page. Here is a direct link to the report PDF file. Includes a summary of his efforts and findings, a couple of diagrams of his setup (including adjustment bolt settings and Coal-trol Digital settings) and a number of photographs of the installation.

http://www.automationcorrect.com/documents/Harman_Magnum_Stoker_test_1.pdf
pvolcko
 

PostBy: BurninCoalInRI On: Mon Dec 11, 2006 11:15 pm

pvolcko wrote:Hi Al, as far as I know on the Harman's they are 2 motor stoker designs so there is no speed controlling of either motor, just time proportioning.


what daos "2 motor" mean here? my harman has 3 motors, feed, combustion blower, circulation blower, and how would i know if any of them can be speed-regulated?
BurninCoalInRI
 

Coal-trol Digital and Harman Mag Stoker

PostBy: nwaelder On: Tue Dec 12, 2006 12:02 am

Hi Al, as far as I know on the Harman's they are 2 motor stoker designs so there is no speed controlling of either motor, just time proportioning.


I believe Paul is referring to an mode whereby the Coal-trol Digital contols Tri-burner type stoves by speed proportioning the stoker/combustion blower motor.

Hope this helps.
nwaelder
 

PostBy: pvolcko On: Tue Dec 12, 2006 12:22 am

Sorry for the confusion. By "two motor stoker design" I meant two motors on the feeder/stoker mechanism itself, one stoker motor and one combustion blower.

So, I meant to say: as far as I know the Harman's are non-triburner type stoves, 3 motors (stoker, combustion, and convection). In this mode we only time proportion the stoker motor, no speed control involved.
pvolcko
 

PostBy: AL-53 On: Tue Dec 12, 2006 8:22 pm

Paul..I can not get any info as the pdf file comes out blank...

does it work for any one else......


also thanks for clearing that up with the control of the feed motor...

AL
AL-53
 

PostBy: pvolcko On: Tue Dec 12, 2006 9:38 pm

Make sure you have the latest Acrobat Reader:

http://get.adobe.com/reader/otherversions/

Also, the file loads in "progressive" mode so initially it may look blank but if you give it some time it should fill in. If you still can load it let me know and I'll break out the materials into a new web page.
pvolcko