Oakwood Warped Grate

dyner · Jan 21, 2015

Hello

I have been using my Oakwood all winter and have never knowingly ran it so hot that I was afraid to warp the grate but it has happened. I am taking it out of service until I get a new grate. I am new to wood burning so what I need is a list of Never Do's so not to destroy another grate. The only time I get the blue flame torch happening off the grate is when I am dumping ash. I open the flew and then the ash door and work as fast as I can but it still fires up the grate. Any help would be appreciated.

I have posted this twice in wrong forums. Sorry about that folks!

dyner

Woody Stover · Jan 21, 2015

I might have mentioned this, but open the load door to pull less air through the ash grate.

dyner · Jan 21, 2015

Woody Stover said:
I might have mentioned this, but open the load door to pull less air through the ash grate.

Thanks. That does make sense. I will start doing that. By the way, I am not finding how to delete a post after hitting edit? I can edit but there is no way to delete. I am new to this so thanks for trying to help me.

bholler · Jan 21, 2015

I will add what i posted on one of your other posts. Just about every one of those stoves that i have worked on has a warped grate it seems to be an issue with them.

Woody Stover · Jan 21, 2015

Click on a moderator's name in their avatar and start a conversation to ask them to delete the other threads.

BrotherBart · Jan 21, 2015

Done. I think I got them all.

dyner · Jan 21, 2015

Donk4kyv said:
This is my 4th burning season with the Oakwood. I think my grate warped the 2nd year I had it. I don't recall ever over-firing the stove. I haven't replaced the grate; I just kept on using it. The only problem is that it makes it a little harder to clear the ashes with the fire still burning. I can't see how it could affect safety or the operation of the stove. I even mentioned this to the people I bought the stove from. They said "don't worry about it" and didn't seem to think the warped grate was serious enough a problem to bother replacing it, even though they would have made money selling me a new one.

You want to maintain a couple of inches of red hot coals in order to maintain a good burn. The instruction book even says that. If that's enough to overheat the grate and causes it to warp, I don't know what you could do to avoid the problem. I think they used poor cast quality iron to make it. Looking at the parts list, I see that the grate is not covered by the warranty.

Don

Donk4kyv · Jan 21, 2015

This is my 4th burning season with the Oakwood. I think my grate warped the 2nd year I had it. I don't recall ever over-firing the stove. I haven't replaced the grate; I just kept on using it. The only problem is that it makes it a little harder to clear the ashes with the fire still burning. I can't see how it could affect safety or the operation of the stove. I even mentioned this to the people I bought the stove from. They said "don't worry about it" and didn't seem to think the warped grate was serious enough a problem to bother replacing it, even though they would have made money selling me a new one.

Even if you get a new grate, I can't see why you would have to stop using the stove until the new one arrives. Just use it. The worst thing that could happen would be for the damaged grate to warp some more.

You want to maintain a couple of inches of red hot coals in order to maintain a good burn. The instruction book even says that. If that's enough to overheat the grate and causes it to warp, I don't know what you could do to avoid the problem. I think they used poor cast quality iron to make it. Looking at the parts list, I see that the grate is not covered by the warranty.

I'm not sure what you mean by " blue flame torch happening off the grate".

Don

dyner · Jan 21, 2015

Thanks and I have to agree. I think it's the grate quality as well.

Toploader · Jan 21, 2015

If it's possible that emptying the ashes caused the warping then the solution is to open the front door an inch as well, this will reduce the blast furnace effect of the ash door.

begreen · Jan 21, 2015

Check the ash pan door for leakage with the dollar bill test. You probably already know this but one should never use the ash pan door to supply air for starting a fire.

Donk4kyv · Jan 21, 2015

I admit I sometimes open the ash pan door to re-start the fire with a few sticks of kindling at 3 AM if the fire has died down to just a few live coals before I wake up to check it. But I never would leave it unattended, and this is for only a few seconds, no more than the amount of time the door would be open with the fire running full blast when emptying the ash pan. I can't imagine how this could get things hot enough to warp the grate. I suspect running the door wide open to make like a blast furnace is more like the kind of human error likely damage something.

... and I always make sure the damper is closed when opening the door to empty the ash pan.

begreen · Jan 21, 2015

I wouldn't recommend emptying the ashes when the fire is going full tilt. Best done when the fire has died down in the late coaling stage, just before a refill.

branchburner · Jan 21, 2015

I agree with Don, don't sweat it. I got my stove used, one year old, and noticed the grate was quite warped. Got a new one, and it warped a bit too. Don't think it comes from overfiring or emptying the ashes, but from normal (=hard) use. Using a warped grate will not be a problem for burning.

A couple things you can try if the warped grate interferes with ash removal: pound out the worst of the warp, or flip the grate over so the top is convex rather than concave.

I ended up using both grates at once (and still do) to reduce some of the smaller coals falling through into the ashpan. Could be my imagination, but seems like I can get a deeper coal bed more quickly with the less coarse opening below the fire that the doubled-up grate provides.

BTW, if you want to monitor temps to make sure you don't overfire, be sure to read the temps off the back of the stove where the AB is. I have seen mine around 800f when the top was about 600f (normally those temps are more like 650f and 500f). Running the stove with air half open, or more, can easily get me to that higher range.

Donk4kyv · Jan 22, 2015

I wonder if you could pound out the warp without cracking the grate. Cast iron is not usually flexible like steel, but has a consistency more like that of fired clay or ceramic. If one had access to a blacksmith's forge to heat it orange hot, that might make it temporarily flexible enough to bend back straight. I know I never heat the grate in the stove that hot, even with the hottest fire. And no, I don't empty the ash pan with a raging hot fire, but I often do so with more than just smouldering red-hot charcoals.

I have one theory about the warp, just a thought. Perhaps the grate expands when it gets hot, but the rectangular hole in the floor of the firebox allows it to only expand so far, and then it warps upwards in the middle as it gets too long to fit the hole. Maybe reducing the length of the grate by about 1/8", by taking off 1/16" from each end using the coarse wheel on a bench grinder, would eliminate the problem by giving the grate a little more leeway to expand.

dyner · Jan 23, 2015

Donk4kyv said:
This is my 4th burning season with the Oakwood. I think my grate warped the 2nd year I had it. I don't recall ever over-firing the stove. I haven't replaced the grate; I just kept on using it. The only problem is that it makes it a little harder to clear the ashes with the fire still burning. I can't see how it could affect safety or the operation of the stove. I even mentioned this to the people I bought the stove from. They said "don't worry about it" and didn't seem to think the warped grate was serious enough a problem to bother replacing it, even though they would have made money selling me a new one.

Even if you get a new grate, I can't see why you would have to stop using the stove until the new one arrives. Just use it. The worst thing that could happen would be for the damaged grate to warp some more.

You want to maintain a couple of inches of red hot coals in order to maintain a good burn. The instruction book even says that. If that's enough to overheat the grate and causes it to warp, I don't know what you could do to avoid the problem. I think they used poor cast quality iron to make it. Looking at the parts list, I see that the grate is not covered by the warranty.

I'm not sure what you mean by " blue flame torch happening off the grate".

Don

Don, I was just referring to the blasting fire torch like condition that occurs through grate when I open ash door with flew open. With the Harman Oakwood they say not to open any doors with flew closed.

dyner · Jan 23, 2015

Donk4kyv said:
I wonder if you could pound out the warp without cracking the grate. Cast iron is not usually flexible like steel, but has a consistency more like that of fired clay or ceramic. If one had access to a blacksmith's forge to heat it orange hot, that might make it temporarily flexible enough to bend back straight. I know I never heat the grate in the stove that hot, even with the hottest fire. And no, I don't empty the ash pan with a raging hot fire, but I often do so with more than just smouldering red-hot charcoals.

I have one theory about the warp, just a thought. Perhaps the grate expands when it gets hot, but the rectangular hole in the floor of the firebox allows it to only expand so far, and then it warps upwards in the middle as it gets too long to fit the hole. Maybe reducing the length of the grate by about 1/8", by taking off 1/16" from each end using the coarse wheel on a bench grinder, would eliminate the problem by giving the grate a little more leeway to expand.

I like your theory. Not sure I will do that, but thanks for input.

branchburner · Jan 23, 2015

dyner said:
the blasting fire torch like condition that occurs through grate

I get around this by only emptying ashes when the fire is low, or nearly out. I usually first burn the coal bed down a bit by opening the air fully for a while, and then shut the air all the way for 10-15 minutes before emptying ashes. That lowers the stove temp and kills the previously glowing coals.

BTW, it will not hurt to leave the bypass damper closed if you are emptying ashes at this stage, so long as the process is done quickly. Opening the ashpan door is going to force air up the flue whether the bypass is open or closed, but leaving it closed will hinder the airflow and reduce the blowtorch effect a bit.

Considering you can close the door after the 5-10 seconds it takes to remove (and then replace) the ashpan, it really is a non-issue. Even with a roaring fire, 5 seconds with that door open is not going to make or break an overfire condition. If you have the primary air fully shut before opening that door, the effect over a few seconds should be minimal.

Donk4kyv · Jan 23, 2015

Sometimes opening the ash pan door with the damper closed lets stinky fumes into the room.

Occasionally it takes me longer than 5 seconds to remove the pan. It seems to temporarily warp and twist when hot, and I have to manipulate it with gloved hand or with poker to get it to come out.

I would think the least damage the blast furnace effect would do would be to the grate, since fresh air is passing up through the grate and blowing the heat and flames upwards, away from the grate. I would worry more about overheating the stove pipe or starting a chimney fire if there is any creosote accumulated in the flue. A nice thick coal bed resting on the grate is going to heat it, in any case.

I have NEVER set off my CO detector when opening any of the stove doors, even when I occasionally attempt to re-load after forgetting to open the by-pass damper. OTOH, I seem to set off the smoke detector every time I re-load, unless the fire has burnt completely down to nothing but red-hot coals.

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