EFM Wood/Coal Boiler Add-On

Recently installed a EFM Wood/Coal Boiler in garage with 1" pex supply/return to Oil Boiler in basement. I started out burning wood but was unable to hold fire overnight. Recently switched to Chestnut Coal which burns great and holds overnight, however, gray/white coal clinkers jamming grates and falling through into ash pan. It seems the coal burns great on top, but doesn't burn after fresh coal put over top. I recently removed the grates (2) and considering a screen or angle over top to keep unburnt coal from jamming grates. Looking for suggestions.

Mark, how often are you shaking the grates?

Do you have any kind of draft control installed?

Rob, I was told to shake it once daily which works for a day or two, however, the longer it goes the worse it burns. Seems the ash and unburnt coal blocks the updraft, so then I need to poke the clinkers out of the grates and pretty soon all the ash is in the pan. I think the grates are too far apart and seen the new EFM's have 3 grates, (maybe closer together)?

Yes, it has a draft in the ash pan door opened by a chain/arm controlled by water temp. It is normally open.

You should be shaking it down twice per day. Shake until you see red embers dropping in the ash pan.

mark wrote:I recently removed the grates (2) and considering a screen or angle over top to keep unburnt coal from jamming grates. Looking for suggestions.

I've never seen this done or considered. It seems to me it would hinder clearing ash. As a matter of fact I don't think ash would be able to be shaken out at all with this arrangement. I've never tried it but doesn't make sense to me it would be in the least bit helpful.

Like Rob advised, shake twice a day. You want to see some red embers falling into the ash pan and an orange glow radiating down thru the grates. If its jamming, try a less aggressive shake, short choppy quick strokes on the shaker handle. Experiment with different shaking technique. If a something lodges in the grates don't force it, it could brake. Cast iron is strong but brittle. Either let the lodged piece burn up or go after it from underneath with a poker tool.