My Koker Has a V Shaped Burn and Coal Falling Off the Grate.

nludke · Post by **nludke** » Wed. Jan. 04, 2017 9:57 pm

I've had a v shaped burn all winter on my koker direct vent. I can't get rid of it. At full burn hot coals are falling off the grate. If I turn the stove down by turning the nut in the back, the stove won't produce enough heat to heat my house. Not sure what's causing it. This fall I replaced my combustion fan/motor, direct vent motor, and had new screws put into my pusher bar.

2001Sierra · Post by **2001Sierra** » Wed. Jan. 04, 2017 10:00 pm

Are the grates air holes clean, and are the grates sealed properly?

nludke · Post by **nludke** » Wed. Jan. 04, 2017 10:05 pm

Last week I cleaned all holes with a drill bit and sucked out the fines under the grate. I've never removed the grate itself, just removed combustion motor and cleaned from there.

Post by **Lightning** » Wed. Jan. 04, 2017 10:14 pm

This is probably basic but, could coal fines be collecting under the burn plate? The fines could then obstruct the combustion air flow up thru the coal.

Oops lol, sorry I just saw your post.

nludke · Post by **nludke** » Wed. Jan. 04, 2017 10:22 pm

That's what I thought, that's why I cleaned out under the grate. No change.

nludke · Post by **nludke** » Wed. Jan. 04, 2017 10:29 pm

Could my v shaped burn have anything to do with how the screws are adjusted on my pusher bar?

titleist1 · Post by **titleist1** » Wed. Jan. 04, 2017 11:16 pm

is the bottom of the 'V' the only burning coals going into the ash pan at full burn? And is the coal burned up in the parts outside the burning 'V' or not completely burned?

if it is all burned up on the sides that would indicate more than enough air is getting through the sides of the grate to fully burn the coal. compared to the middle of the grate area which isn't getting enough air to burn it up before being pushed off the grate.

nludke · Post by **nludke** » Thu. Jan. 05, 2017 8:34 am

Yes, you described it exactly. So how do I remedy the situation. The holes are clean, the space under the grate was sucked out a week ago and I have a new combustion fan.

McGiever · Post by **McGiever** » Thu. Jan. 05, 2017 10:09 am

Excess air leakage compared to center portion of grate(s)...seal to control even air distribution across the entire grate.
Furnace cement at gaps/joints wiped w/ a wet finger should do the job, then allow some drying time.

titleist1 · Post by **titleist1** » Thu. Jan. 05, 2017 11:10 am

I am not familiar with the grate set up on a Koker 160. Is it a one piece grate or are there two grates side by side? If a two grates side by side then don't cement the center seam so some air can get up through there to burn the center of the coal bed. If a one piece then double check the holes in the middle of the grate to be sure they are as clean as the holes on the sides.

As Mcgiever suggested seal the edges, there might be excess air escaping there that could be cheating airflow at the center of the coal bed.

2001Sierra · Post by **2001Sierra** » Thu. Jan. 05, 2017 2:02 pm

My Keystoker 90 has 2 grates side by side. I seal the perimeter, as well as the seam where the two meet. The seam is not an air passge, the drilled holes are. From the factory the center is not sealed but remember when new everything fits much better.

McGiever · Post by **McGiever** » Thu. Jan. 05, 2017 2:49 pm

And notice the Keystoker grate sections are ship-lapped.

Bigger Keystoker units have multiple ship-lapped ~3" sections added to obtain the incremental higher outputs.

nludke · Post by **nludke** » Thu. Jan. 05, 2017 3:35 pm

I'll give it a try when I get home. Can I restart my fire right after I apply the furnace cement or do I have to wait for it to dry on its own?

WNY · Post by **WNY** » Thu. Jan. 05, 2017 5:19 pm

they are all similiar in design, here's a good write up I did a while ago.

You might have an air leak or something, make sure your grates and the sides are clean and smooth and sealed properly. If rough, the coal/ash can stick and cause it to feed strange.

Cleaning & Sealing Burn Grate

Olllotj · Post by **Olllotj** » Thu. Jan. 05, 2017 6:04 pm

It's gotta dry on it's own. A heat gun / hair dryer or fan would speed up the process.

My Koker Has a V Shaped Burn and Coal Falling Off the Grate.

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