Overdraft

[hamsey]

Talked to Ray @ Hearthstone about the ongoing issue of charcoal in my Clydesdale. Based on what I described to him he said it sounds like an overdraft issue. He mentioned this on another occasion and when I talked to my dealer about he said he has never heard about it.

Got home tonight and reloaded the stove once it got going I checked it a few times. Cold stove -0.05, active burn: -0.15, -0.14, -0.12 & -0.15. Called Hearthstone again and talked to Ray who confirmed that I have an overdraft issue.

So now what can be done about it? 6" S.S. Liner 22-23 feet long. Read about a restrictor plate or cap. Have a call into my sweep but have not heard back from him.

Thanks!

 

[pen]

Wish it could be a stove pipe damper.

Thinking you'll need to restrict secondary air.

Did they give you advice at all? Or on where / how to restrict air on this unit since they recognize the problem?

 

[hamsey]

Restrictor plate or cap at the top of the liner. No mention of doing anything to the stove just the liner. Bypass damper is out as is a barometric damper.

 

[Hogwildz]

I have thought about this situation often, and was wondering if an inline pipe damper could be installed between the liner and stove outlet, with may a long rod attached to the damper lever running through a hole in the surround, and a knob on the end to push and pull activating the damper open & closed. Maybe I should invent it and go on the Shark Tank.

 

[bholler]

I have thought about this situation often, and was wondering if an inline pipe damper could be installed between the liner and stove outlet, with may a long rod attached to the damper lever running through a hole in the surround, and a knob on the end to push and pull activating the damper open & closed. Maybe I should invent it and go on the Shark Tank.

I have seen a few homemade ones it makes it a bit of a pain to clean but with really high stacks sometimes it is needed

 

[velvetfoot]

Overdraft causes charcoaling? Your stove can't control the air? That only happens to me with to LITTLE air. But, they're the experts.

 

[hamsey]

Velvet,

That is what I was thinking. It was ruled out because my glass stays clean (except for a tiny bit in the lower corners) and the fact that I have really lousy burn times. No problem getting it going and after the gassing stage the wood in the back just goes to big lumps of charcoal. I did put a draft meter on it to confirm it. Never though I would use the built in draft port.

If it matters the weather conditions were at the time of the test: 35* outside, light rain/overcast. Definitely not ideal draft conditions. Going to give Ray another call and have him explain it again to me.

 

[mopar440_6]

Hamsey, I'm far from even being considered an amateur with wood burning but here is a post from BrotherBart that may be of interest to your issue.

Well, it is that time of the season...

http://www.gulland.ca/florida_bungalow_syndrome.htm

 

[velvetfoot]

My chimney is 25' and I have no problem, except that I do get charcoaling if I keep it real low through the whole cycle without opening the air when things start slowing down. Reloading a bunch, trying to get max heat, is also problematic, but I think that's just the nature of things.

Not sure if this was covered in the other thread, but your wood is dry?

 

[hamsey]

Mopar,

Thanks for the link. I did print it out and read it. That is when I decided to give Hearthstone another call. With my old Jotul I still had lousy burn times but at least it got to the coaling stage and then turned to ash. I just could not leave that stove for the first hour because I was worried about over firing it. This one is the opposite. Never thought about overdraft with the Jotul and I had no way to check it. Does make sense now though.

 

[velvetfoot]

Well, you've done a lot of research already, but if the flames are controllable with your new stove, wouldn't it be coping with whatever draft there is?

 

[hamsey]

Wood is not the best between 19 and 22 percent. Talked about that also but he did not seem too concerned about it. Opening up the air when things start slowing down is what I am doing now and it helps but when I come home after work or going out I have a massive pile of charcoal and that is leaving the air about half. Lousy burn times for sure. I am burning white ash and trying not to burn any oak. I do get that hollow sound when I bang a couple of pieces together.

If this is the nature of the beast then I need to find another stove. I need a set and forget stove for my wife. We have already had several arguments about it.

 

[hamsey]

Well, you've done a lot of research already, but if the flames are controllable with your new stove, wouldn't it be coping with whatever draft there is?

Air is fully closed with nice secondaries and that is with subpar 5 to 6 inch girth white ash. Would not think that I could close it down all the way.

More details. Interior chimney. Draft range from Hearthstone is -0.05 to -0.08. My draft as measured from a UEi EM151 Electric Manometer -0.12 to -0.15 Double (mostly) what the draft should be.

 

[velvetfoot]

That is an interesting article, for sure. Though the charcoaling puzzles me, the quick consumption (and big flames?) seem to support your hypothesis, I don't know if -.15 is low pressure or not. What does the manual say? Has someone else modified the stove by covering the secondary inlet, wherever that may be?

 

[DougA]

If you have to 'open up the air when things slow down' & 'lousy burn times' just screams to me of wood problems. 19-22% should not cause that problem. Was your wood standing dead when cut? If so, it probably is spunky. If not, I think you moisture meter is wrong.
If you have good draft or even too much draft, good wood will be burning completely to ashes with the air control on low, once the fire is going.

I've got a Hearthstone and I suspect the design and controls are similar. Your problems appear to be the opposite of what I have experienced. How are you taking the readings?

 

[velvetfoot]

subpar 5 to 6 inch girth white ash

Subpar? In what way? Those seem like pretty good size splits to me. Maybe you'd get less charcoal chunks if they were split once more?
Maybe it's been rehashed, but many times the first year doesn't go that smooth because of the wood.
On the domestic front, I'd recommend sticking with the stove for now, try to get as much heat out of it as you can, leave the thermostat wherever she likes it, and wait til next year when the wood is better. That's assuming there's no genius factory fix.
Even my wife reloaded the insert during the day, which it needed only rarely. I she can do it... She's complaining now about the 69* in the living room while I'm testing the pellet boiler when it's cold outside. She got used to that nice heat from the insert, which will, incidentally, be fired up today now that I've got the boiler more dialed in.

 

[hamsey]

Manual just talks about using the draft port. I checked it last week and had a negative number and figured that I did something wrong. After a very frustrating weekend of always having to attend to the stove I decided to give Hearthstone a call and talk about it. This time I wrote down the numbers and called back with them then and there and confirmed that it is overdrafting.

When I first started taking my readings I would just split a piece of wood and measure on the fresh split face pushing the pins in as far as I can. I was getting between 17 and 19 percent. Then I remember reading about a temperature correction table, found that and did the test again. Measure fresh split face with MM and IR gun and used the correction table to discover that my wood is between 19 and 22 percent. Not the best for sure but not that bad and better than it was last year.

 

[hamsey]

Well my problem before was too small of splits. 5 to 6 inches is the biggest most are 3 or 4 inches. I put two of the big pieces and a 4 or 5 inch half round in for the overnight burn usually around 10. I wake up between 1 and 2 and would have to reload if there is any chance of keeping the furnace off. It does put out nice heat but not for very long. I really though it is a wood issue until I talked to hearthstone. If there is a large bed of coals I throw 3 or 4 8" Envi blocks when I check them later same thing front is burning and the back is black. I need to find some properly kiln dried wood to test.

Domestic front my wife does reload but she cannot be bothered with having to constantly tend it. When the house gets above 65 she starts to complain that it is too warm. I tell her I need to up the temp due to the heat loss during the night which is about 5 or 6 degrees.

I am going to wait and see but in the mean time I would like to pursue the recommendation from Hearthstone for piece of mind.

 

[DougA]

Bring a freshly split piece of wood inside, then measure it with the MM once it has reached room temp. Frozen wood will measure very low and I would not trust a correction table myself. Spunky wood is a different matter entirely.

Your stove is 2.4 cu ft. You should be getting an overnight (8 hr. ) burn when you are using perfect hardwood and the stove is stuffed as full as possible - jammed. Two pieces and a few small ones seems to me like it's not as full as possible.

Don't forget that the super cold weather we have been experiencing will cause more draft than usual.

 

[kennyp2339]

I had excessive coaling when I re-installed my freestanding stove in the basement, I assumed the opposite at first <to little draft, but one day I lite the fire and nothing else was going on, I heard a slight whistle coming from my stove pipe, I knew right then that I has sucking in to much air, I installed a pipe damper and I experienced much more control on the stove, steadier temps and of course less coals.

 

[velvetfoot]

Restrictor plate or cap at the top of the liner.

I wonder if those solutions could have some bad effects during other times of the year, like that Guilford (sp?) article indicated?
Wouldn't an easily-reversible fix on the stove, if available, be more desirable?

 

[hamsey]

That is all the wood that I can fit in due to coals. Even raking them forward and trying to burn them down they start to charcoal.

Funny as I do hear a whistle at first I thought it was the warped door but still get the same thing with the new door. Not sure where it is coming from.

I took the draft measurement when it was 35* out and light rain.

 

[hamsey]

Fix on the stove yes based on that article as it sounds like the best option. I just do not know what or where. And yes modifying the cap could have consequences in the shoulder season. There has got to be option though.

Copied from above. I thought it was the last post:

"More details. Interior chimney. Draft range from Hearthstone is -0.05 to -0.08. My draft as measured from a UEi EM151 Electric Manometer -0.12 to -0.15 Double (mostly) what the draft should be."

 

[velvetfoot]

There have been threads about a whistle on other makes, but I don't think they were the total source of secondary air.

 

[mopar440_6]

Is there any chance the primary air inlet is clogged? Charcoal is created when wood is out gassed in a low oxygen environment. My thought is that even though you have too much draft, it could all be coming through the secondaries and there is no primary air coming in to burn down the coals. IE the secondaries are burning off all of the wood gas and smoke leaving you with charcoal instead of hot coals burning down with the primary air. Just a thought.