Harman Mag Stoker Grates

Hi Guys im soon ready to fire stoker up here in PA Im having problems with grates warping causing fire to burn in a arrow at end of grate instead of being straight....these grates were brand new and burnt for 2 months only.when burning I have to shut down and straightned up grates grates know are $70.00 a set know they are to expensive to keep buying I have stove drafts set with manometer .04 at pipe and .03 .04 ,at firebox also checked gasket around grate holder good this condition has been happening since stove was new 2 years ago any ideas why these grates are doing this.Also cannot get any answers from Harman dealers some say stove is over fired .....how can a stoker overfire.....my stove does not run continius maybe a hour to satisfy thermostat....answers would be appreciated
Harman Magnum Stoker

I also have a mag stoker and with all my searchinh I found that if you plug the combustion air fan in direct to the wall that should keep the grates cool when your stove is ideling. when the air stops the grates have no way too cool themselves. My stove is only 2 years old but have had no problems yet. hope this helps.

My Harman stoker boiler uses the same stoker and grates. Mine are going into their 8th season and still look fine. I would have to agree it was likley from overfiring. In the manual there are pictures of the fire. One shows what overfiring would look like. Does your stove dump live coal off of the end of the grate? It's amazing that those are only two months old. Something is very wrong. Not surprised your Harman dealer is no help though.

Do you have hot coals falling off the grate?? If not are they an inch back on max fire? if so then you are probably not over firing the stove. Looking at the picture the part that is warped is the center of the grates, but it looks like the back closest to the stoker is getting really hot(judging from the discolored look). I wonder if the casting that the grates sit on is not true, allowing air to go there instead of all going through the grate holes. This would allow that fire even on idle to burn really hot but not be noticed. Can you get a straight edge in there and check this, or maybe cement the grates in, I know they are supposed to be free floating, but judging from that picture the fire is getting air from somewhere other than the holes in the grate.
Keep us posted and best of luck, Eric

70 Dollars, wow

I bought my set couple of years ago, never used them, since I am still experimenting, anyway, I was shocked how reasonable they were to purchase

16.00 Dollars.

I guess I need to be careful and not abuse them

Hi guys thanks for the input on the problem im having....to answer question on hot coals dropping off grate....i have a good 1 inch of ash before they drop...when I first got stove I was only burning 1 1/2 dot and would at least 4 inches of ash....and grates would still look like these.what would you use to cement grates and where would u put cement...anyone cement there grates? I got different coal this year also to try I was using a red ash coal that would sheet at end of great and would burn hot.....more replies would be appreciated....

Riceburner78 wrote:I also have a mag stoker and with all my searchinh I found that if you plug the combustion air fan in direct to the wall that should keep the grates cool when your stove is ideling. when the air stops the grates have no way too cool themselves. My stove is only 2 years old but have had no problems yet. hope this helps.

Like riceburner said I would plug your combustion blower in all the time. If you are not over firing then the grates are warping, cause they are not supported evenly allowing them to distort. Or like I said it seems like you are getting air in at the begining of the burn plate where no air is supposed to be. The furnace cement was just an idea, I would glue them in at the front, don't know if it would work or what problems it might cause, but maybe worth a try
Best of luck, Eric

Make sure your pan is clean under the grate's when you take the grate's off, sometime's ash build's up in the pan and the air from the comb. blower wont come up through the grate's as it is supposed to. Coalkirk would be able to explain this better than I did. I know my mag. had ash in the pan and wasnt burning the coal evenly, I cleaned it out and it really made a difference. Just something to check for, might help you out. Maybe your air from the comb. blower is just coming up in a certain area and creating a " hot spot " on your grate's , the ash built up in the pan may be blocking the air from the comb. blower and not letting it come up through the entire grate as it should.

Another thing to check I forgot to mention, check the restricter plate for the comb. blower, just maybe you are getting to much air under the grates. My mag. has a cover that you can adjust the amount of air that the comb. blower can blow to burn the coal.

hi guys thanks for replies I went to a Harman dealer today and asked him about my grates he told me to cement grates in,the new Harman super mag was there they use the same grates and holder as the mag stoker and the grates are cemented in from the factory.believe it I talked to a rep at Harman factory today also he told me to cement grates also,he said the super mag and dvc500 are cemented at factory.....im gonna try it on mine in about 2 weeks when I start stoker up.....also I have combustion fan flap about half open to get .04 on draft gauge....and I barely get any ash out under grates.....i think cementing grates is a logical thing to do because it would seal them on sides making all the air to come out holes in grates where its suppose to to keep grates cool..........

Hi guys I glued my grates in over the weekend im gonna fire it up this weekend ,,,,i talked to a Harman dealer that would give me some answers he told me to glue grates in with furnance cement.....the DVC-500 and the new super mag grates are glued in from the factory....does anyone know if they are the same grates as magnum stoker? also I called and spoke to a guy at Harman stoves co. he said to glue them in also I asked him what the reason was Harman gluing grates in super and dvc500 he could not give me a answer.....does anyone know why they glue them in ........i think gluing them in will promote more air flow through holes in grates rather than air sneeking up the sides and possibly the back towards fire.......did anyone try gluing grates in mag stoker.....did it make a difference?.........

well heating with Harman mag for 3 months now......fireline is straight telling me grates are staying tight in center and not warping ......i cemented new grates in ....in front back side and in the middle stove burning good......just hope I can get furnance cement off at end off season to remove grates to clean up for summer

I have run my mag for 5 years and ran it hard with no grate problems, but I do see a lot of people bying replacement grates at the local hardware store. Almost every 3rd trip in I see someone getting new grates. Makes me wonder if somehow the grates might have a deficencey of some type as they cant all be overfireing the stove?

GAMESNIPER wrote:Hi guys I glued my grates in over the weekend im gonna fire it up this weekend ,,,,i talked to a Harman dealer that would give me some answers he told me to glue grates in with furnance cement.....the DVC-500 and the new super mag grates are glued in from the factory....does anyone know if they are the same grates as magnum stoker? also I called and spoke to a guy at Harman stoves co. he said to glue them in also I asked him what the reason was Harman gluing grates in super and dvc500 he could not give me a answer.....does anyone know why they glue them in ........i think gluing them in will promote more air flow through holes in grates rather than air sneeking up the sides and possibly the back towards fire.......did anyone try gluing grates in mag stoker.....did it make a difference?.........

Harman may cement them in when they manufacture them to lessen replacements under warranty period...after that they have dealers just sell you some more.

I guess it's just a business (profit) decision they'd rather not disclose.