Ash Buildup in Firebox

Greetings All

New to this forum today. This is a great forum, and I hope some of you pros can help me. I have a Harman Mark III and I'm into my 3rd heating season. My problem is after a few days of burning, the front part of the firebox gets an accumulation of ash approx 3" wide. It appears it is not grating into the ash pan properly. I use short choppy strokes and the rest of the bed grates well, with the exception of the front. After about a week or two the ash spreads and the burning coal bed tends to get smaller and smaller. At this point I have to burnout, cleanout and start a new fire. This has always been the case since I bought the stove in 2008.

Any suggestions is greatly appreciated.

Welcome to the forum!!! This is a common issue with the Mark series stoves. I use a fireplace poker to scrape along the front edge of the firebox every 2-3 days or so during the very cold weather (less often when not burning as intense) to "shake" the ash away in that location, then I fill it back up in front with coal. I don't have to let the stove burn out, it recovers nicely.

edit just to clarify....I am scraping with the poker from above, not below, holding the poker vertical through the loading door, just two or three pulls across the very front of the firebox.

Welcome to the forum:

The front grate in the Mark series stoves has a solid bar along the front of the grate, just below the door opening.. the back of the grate is next to another grate.. So when you shake, the grate-against-grate portions get plenty of aggitation to shake down and grind up the ash.. But the front of the front grate is next to the motionless front of the firebox.. so ash builds up, blocking the combusition air.

If you try more agressive shaking, you end up dropping to many live coals into the ashpan, and wasting coal..

You can scrape along the front with a poker, like suggested above.

Or you can make a small poker to use from underneath, that you poke into the gap in the fingers of the front grate.. once you do this you will get several small avalanches of ash, and with the air restored, the coal fire will again move to the front of the firebox..

I suggest using the wire frame from a political sign. The large signs use 1/4" or 3/16" wire, perfect for your needs. Remove the wire frame, cut the wire so you have a 3-4" 'L' on the end, and if you want, put a wooden handle on the other end.. Open the ashpan door, wiggle the new poker above the pan and along the front of the first grate, 'flossing' between the teeth of the grate.. You'll soon get the hang of it, and be able to keep the accumulation of ash to a minimum.

Greg L

I am new to coal fired heating, but I am also using a Harman Mark, but mine is a II. The ash builts up along the front also and blocks the air flow. I took a piece of 1/4" round stock that I had in the shop and made a pocker to come up from the bottom. 3-4 inches is just too long, the hook I am using is 1 1/2" and works great. You still have to do a good bit of shaking, but it will restore air flow every time.

titleist1 wrote:Welcome to the forum!!! This is a common issue with the Mark series stoves. I use a fireplace poker to scrape along the front edge of the firebox every 2-3 days or so during the very cold weather (less often when not burning as intense) to "shake" the ash away in that location, then I fill it back up in front with coal. I don't have to let the stove burn out, it recovers nicely.

edit just to clarify....I am scraping with the poker from above, not below, holding the poker vertical through the loading door, just two or three pulls across the very front of the firebox.

Do you have the grate closed when scraping or do you have it open a bit?

Thanx for the education on the grate. These are all excellent ideas and I will give them all a try and see what works for me. Will keep ya posted on the outcome.

Burnin in Trevorton wrote:

titleist1 wrote:Welcome to the forum!!! This is a common issue with the Mark series stoves. I use a fireplace poker to scrape along the front edge of the firebox every 2-3 days or so during the very cold weather (less often when not burning as intense) to "shake" the ash away in that location, then I fill it back up in front with coal. I don't have to let the stove burn out, it recovers nicely.

edit just to clarify....I am scraping with the poker from above, not below, holding the poker vertical through the loading door, just two or three pulls across the very front of the firebox.

Do you have the grate closed when scraping or do you have it open a bit?

Closed... after using the poker I shake again a little and the powdery ash that didn't already fall through from scraping falls through at the front of the grates.