Harman Grates: How to keep them clean and clear

Harman Grates: How to keep them clean and clear

PostBy: Cool Customer On: Fri Mar 14, 2014 4:17 pm

Near the end of my first season burning coal in my Harman Mark I. Generally it's gone well.

I had some problems early on before I was told you have to poke up through every opening in the grates periodically to keep it drafting. So I made a tool, a brake line about 16" long with a 90 degree bend 2" from the end. Stuck an old wooden handle on it, and have been poking/scraping each opening in the grates most every time I shake and load (every 12 hours generally).

I'm not too happy with the tool and the cleaning process. Does anyone with a Harman have a tool that works really well for this purpose? Can you describe it and how you use it, or better yet a picture ??

Thanks in advance, since I won't check for reaponses until tomorrow.
Cool Customer
Hand Fed Coal Stove: Harman Mark I

Re: Harman Grates: How to keep them clean and clear

PostBy: J F Graham On: Fri Mar 14, 2014 4:50 pm

CC: This is also my first year of burning coal, after 40 yrs with wood. The folks here are GREAT!! Am sure there will be others to offer suggestions, but I have a Harman SF 160 and have learned quite a bit. What I was guilty of not doing was not poking enough; as there were "dead spots" in the ash pan. By that I mean, when you shake down there should be illumination in the entire ash pan from the glowing coals above. If you shake down and see a shadowy area, that means there is still a layer of ash preventing air flow. This can also be observed from above; by looking in the feed door. If there are areas not burning EQUALLY, particularly corners and edges the coals need to be poked. In my particular case I poke/rake the coal bed at least once a day some time twice. Some may say that's too much; but in my opinion 'why not'. Only the ashes and really fines will penetrate the grates, and you will have an even air flow. I have actually decreased coal consumption by doing this. Instead part of the coal bed doing the work, now I have the whole bed working. What I use is a 3 ft piece of 5/16" smooth rod bent to "ALMOST" a 90 angle The angle is 8" in length ground to a dull point. This way if I have a full bed I can still reach bottom and grind away, thereby chewing up any stubborn ash. On a once a day cycle I have also learned to do the poking In early afternoon so any fines in the grates can burn before shaking that evening. Wife just got home and she is tec rep :D so if you need pics of poked, I can make it happen. Good luck
J F Graham

Re: Harman Grates: How to keep them clean and clear

PostBy: lowfog01 On: Fri Mar 14, 2014 7:27 pm

I've never heard of "poke up through every opening in the grates periodically to keep it drafting" and I've been burning a Mark II for 6 years and a Mark I for 1. I don't have a problem clearing the ash in either of my stoves. It does happen, just not often.

If I notice that fire is burning cool and I think it's because of the ash build up I will take my 1/4" steel rod that I put a wooden handle on and poke the coal bed in 5 or 6 spots across the grates. I pay particular attention to just behind the front fire bricks. That spot seems to really build up the ash; probably because of the over the fire air wash built into the door. Once that's done, I close the load door, open the air controller a bit so I can watch for the glow through it and shake. I use short, choppy stokes. Doing the shake this way allows me to shake the stove with the door closed and keeps the flyash inside the stove and out of my living space. I stop shaking the minute I feel any resistance and I see the glow is strong.

I reset the air controller and wait a 5 minutes before I open the ash pan door to check it. That allows the flyash to settle. I shake my stove twice a day and empty the ash pan once.

As I said, I've don't have an issue with ash blocking my draft. In fact, I tend to use the ash TO block the draft and give me a longer, cooler burn. Do you have a thermometer on the stove front? That can tell you a lot about how your stove is burning. In my Mark I I don't often get a fire which has the blue ladies dancing. Instead I get a slow smoldering fire. The stove looks dead but the thermometer is registering a temperature. That shows me that air is moving through the coal bed, i.e. I have a draft.

I hope that I have helped you in some way. If you have questions or comments, please post again. Lisa
Hand Fed Coal Stove: Mark II & Mark I

Re: Harman Grates: How to keep them clean and clear

PostBy: Scottaw On: Fri Mar 14, 2014 11:20 pm

I give my stove a good cleaning about once a week, I'll stir the edges and make sure I have a very strong glow in the pan. Never had to clean every grate, just a few pokes will loosen the whole bed. I do get a lot more heat out of it for the next day or so, but I agree, letting the ash build up can give you a longer smoldering fire.

Just one if those things, learning the individual anomalies of each installation.
Stove/Furnace Make: Hitzer
Stove/Furnace Model: 50-93

Re: Harman Grates: How to keep them clean and clear

PostBy: joeq On: Fri Mar 14, 2014 11:46 pm

I don't know about the differences in your stoves, compared to my Surdiac, but I too rake my grates from underneath, sames as the op. The 3 riddling slots in the front of my stove only allow a marginal method of cleaning the grates. Raking all the slots from below helps drop more ash. The more collected ash choking the coal bed, only starves the fire quicker. Maybe because my coal bed only holds a minimum amount compared to the bigger stoves.
CC, there's a thread from a few days ago, where people showed pics of their tools. Maybe you could get some ideas from it. I'll try and find it, and post the title.
OK, I just went over to the "hand fired coal stoves" column, and found it appropriately titled,"coal tools". Maybe you could use something from it. Good luck.
Hand Fed Coal Stove: Surdiac Gotha 513
Stove/Furnace Make: Oil fired
Stove/Furnace Model: Thermopride

Re: Harman Grates: How to keep them clean and clear

PostBy: dcrane On: Sun Mar 16, 2014 7:19 am

Dead spots and ash clog as a fairly common problem and certainly a square coal bed or a grate system that does not shake across 100% of the coal bed ads to this dilemma as you discovered. Some coal burners have become very adapted to this issue and can indeed use their shake/ash build up as draft control (as you hear Lisa explain), the methods of running your stove are as individual as each others draft and houses. I am one who believes that a slow smoldering burn by using your ash build up as draft control is not as good as ensuring a nice even shake, even burn cycle and even clear glow in the ash area, I would open the MPD and lower door a minute prior to shake/poke to allow draft to keep fly ash in stove as well as get a good hot firebed before loading her up and then utilize the draft knob and mpd to control draft through the burn cycle (this allows for a better more even burn, it allows for ignition of secondary gases before exit out the chimney, it allows for the stove to function as intended (I know poking or scratching each 12 hour cycle is not ideal, but i believe its best). slow smoldering coal beds will stink to high heavens when you walk outside after loading them (I want to burn those gases!)
Hand Fed Coal Stove: Crane 404

Re: Harman Grates: How to keep them clean and clear

PostBy: Hambden Bob On: Sun Mar 16, 2014 12:55 pm

Cool,what size of Anthracite Coal are you burning in that Harman Heat-Maker? :gee:
Hambden Bob
Hot Air Coal Stoker Stove: Harman 1998 Magnum Stoker
Coal Size/Type: Rice-A-Roni !

Re: Harman Grates: How to keep them clean and clear

PostBy: bopper On: Sun Mar 16, 2014 1:37 pm

I too have a Mark I, second full year burning coal. First year I used mostly pea and had more trouble with dead spots and bridging. I now used Nut exclusively and have better results.

I tried to use a heavy duty coat hanger bent at 90 degrees to poke the bottom but that didn't work so well.

Through trial and error I have found this works best for me when reloading twice a day:
1. Open air knob about 50% more than usual.
2. About 7-8 quick choppy shakes of the handle.
3. Poke all 4 corners straight down. (You can usually feel the pockets or voids and the bed will sink by doing this)
4. Poke the center if it was not moving down. (Again poke down and don't stir)
5. Shake again until even glow is visible underneath. (Some burning orange bits will fall through)
6. Add layers and let each one catch.
7. Reset air knob.

Remember everyone's home, draft, insulation, chimney, etc are different. You might be best doing your own controlled experiments after reading all the responses and see what works for you.

Hand Fed Coal Stove: Harman Mark I
Coal Size/Type: Nut

Re: Harman Grates: How to keep them clean and clear

PostBy: lowfog01 On: Mon Mar 17, 2014 3:51 am

As I stated, I've don't have much of a problem with dead spots or bridging in either of my Harmans. I'm able to clear the ash in the Mark I pretty thoroughly by just shaking as I indicated above; I chose not to. My problem is that the Mark I is installed in a tile chimney that has such a strong draft that a small child or cat could be sucked up and never seen again if not watched carefully. ;) I know what a "horrible" problem to have.

That stove is in a very small space, maybe 400 square feet and I can't close the air controller far enough and yet get a widely dispersed burn with just that. I've found that by using the ash to retard the draft and having the air controller open a tad wider, I get a more uniform burn throughout the stove and have a better handle on the heat production. I burn Pea coal exclusively in that stove for the same reason.

I'm extremely happy with how the addition of the Mark I has worked out. I can run both stoves cooler and yet burn the same amount coal as last year for an over all warmer house. Fortunately, I don't have any of the negative side effects that were spoken of in other postings here. The bottom line is I'm a happy camper with how my stoves are burning. Take care, Lisa
Hand Fed Coal Stove: Mark II & Mark I

Re: Harman Grates: How to keep them clean and clear

PostBy: Cool Customer On: Tue Mar 18, 2014 3:37 pm

Lots of good info in replies. I made a new poker/scraper tool, of 3/16 steel rod and longer, with a bigger handle. It does a much quicker job than my less rugged brake line tool. I'd love to make the grate poking/scraping task a once-every-several-days task, and will try poking down the four corners (I've been poking just the middle, thinking that would break up any bridging) to see if that eliminates or reduces the need to poke and scrape the grates clean.

The thing with poking and scraping all the grate openings is it makes the stove burn great and yields consistent heat output at low settings, even increasing a little over 12-24 hours; rather than the decreasing output that I experienced before I started cleaning grates periodically.
Cool Customer
Hand Fed Coal Stove: Harman Mark I