Consolidated Dutchwest Federal Convection Extra large model 288

[SC woodburner]

Please forgive me if this post is inappropriate but I searched the other posts and could not find a definitive answer.

We recently purchased a home with this wood stove, a 1990 model. The stove had not been burned in approximately 8 years. We fired the stove for a month or so and found performance showed a non functioning or partially functioning combustor. The flue and stove pipe had considerable creosote buildup. I also suspect some of the wood I was burning was not sufficiently cured. I found the damper gasket completely missing.

Since then we have cleaned the flue and stove pipe. I overhauled the stove replacing the combustor, upper combustor chamber gasket, damper gasket and all door gaskets. I also cleaned all residue possible from within every compartment. We used Condair parts. I have tested all the door gaskets and she is air tight as best I can tell. I ran a lighter all around the gasket areas and could observe no flame movement to indicate an air leak. I am confident I did a good job on re-gasketing.

I pulled the driest and oldest wood from the shed and this evening I fired up the stove and as normal it took longer to do with no ash bed and a cold stove. The first fire brought stove temps up to 400 degrees. I added two split pieces of oak and at 500-550 degrees on the temp probe I shut the damper and adjusted the primary and secondary air vents to 1.5 turns and 3 turns respectively for a medium/low burn as directed by the operating manual.

Temp probe immediately climbed and climbed and climbed up to near 1700 degrees. I freaked out, shut air vents and opened damper. Temps dropped some so I peeked in and saw the combustor glowing red. I'd call the fire medium at best and it was never roaring. In the last couple hours we've closed the damper and cracked the air vents slightly. Each time the temp has climbed up to around 1600 degrees and we've shut things down again till it dropped, repeat, repeat for about 5 times. Now we have both air vents closed and are still getting 1500 degree probe temps with combustor engaged. It has not back puffed at all and there has been no visible smoke or smell of any around the stove through all this.

I think I have given all pertinent information.

My questions are:
Is the old extremely dried wood the culprit of the over-firing and have I simply gone from one extreme to the other with fuel?

Is the temp probe accurate and if so should I be concerned that I may have risked damage to the combustor?
I ask this because when the temp probe read lower than 1300-1400 degrees I could see no visible red glow when looking up through the fire box grate at it. If I looked in there above those temps it was visibly glowing.

Do I have a draft problem with the stove pipe?

Any advice would be appreciated. Going forward we are going to be very careful and try burning small amounts of wood.
Thank you and again, please pardon a first time rookie poster.

 

[SC woodburner]

I reckon I should have put over-firing in the title somewhere. Again, any advice on something I may be doing wrong would be greatly appreciated.

 

[homebrewz]

Since no one else has responded yet, I'll try and answer a few questions and maybe that will get things rolling. A quick search tells me that combustor temps can get to around 1000 to 1500, but should not exceed 1500 to avoid damage. The combustor may glow, but does not need to be glowing to work.

http://www.woodstovecombustors.com/maintenance.html

You can search around the hearth forum here to see what others report for combustor temps. Several folks on here use combustor/catalyst probes.

Does this stove have a refractory package which houses the combustor, or is it sitting in the cast iron frame work of the stove itself? I know some of the Dutchwest stoves have a refractory.. its possible there is a chunk missing somewhere allowing excess air to enter the secondary combustion chamber.

I don't think its possible for your wood to be too dry, especially in the SC climate. You can look around in the Wood Shed room for discussions about dry wood. That topic comes up occasionally.

You have, and are reading, the owners manual which is great!

Just some thoughts.. good luck.

 

[SC woodburner]

Thank you for the reply. This stove does indeed have a refractory package and you bring up something I hadn't considered. When we disassembled the stove to change the combustor and gaskets I found a small corner of the refractor broken. This piece is approximately 1.5" long and 1" high, sort of a triangle piece at the lower corner of open end front that faces the flue. I pushed the piece gently back into place and replaced the refractor when reassembling the stove top. Not at all to argue, am ignorant of all this, but I don't see how the small part could be letting additional air in but it can't be much as it only separates the combustor from the rest of the area between it and the flue. I will research that and consult the parts supplier we used. Shouldn't be any trouble at all to replace compared to all the work I've done already.

My Wife fed the stove all day but backed off on the amounts loaded, basically only adding a single split each time. She has added single pieces 4 times today over a ten hour period maintaining a 1000 to 1200 temp and only saw one temp spike to 1500.

Again, thank you for taking the time to respond. I will update the post with any changes.

 

[homebrewz]

OK, that might not be it, but it was just a thought. Those refractories are kind of a pain.. they break down over time with normal use and are usually as much, or more expensive than the catalyst to replace.

If you have a secondary air inlet, like the kind operated by a bi-metal spring and probe, that can also be a source of extra draft. The probe and spring get dirty over time and then they don't work right. Not sure if your stove has one, but its something else to look into.

 

[begreen]

This is a catalytic stove. Is the cat brand new? They can burn hot initially. What condition is the baffle in on the stove?

The quick take off probably was the extra dry wood. Try it with some normal sized cord wood and see how she runs.

PS: moving this to the main forum it is an EPA stove.
PPS: How tall is the chimney on the stove?

 

[SC woodburner]

Yes the cat is brand new. The chimney is approximately 15' and straight up, no turns. The refractor was in pretty good shape. We also replaced the temp probe.

I do believe I have figured out what was the problem. Condair's new cat comes with an "expanding gasket" taped around it. The instructions say the tape will burn off during initial use. I believe the gasket had not expanded and that's where the air had to be coming from on the first fire. Funny but the instructions made no warning for this and we followed everything explicitly. So far the stove has been a bit more controllable but we haven't really loaded it up either. I figure we'll work back up to a confident level slowly. This was more of operator anxiety I guess and having your thoughts really helped. Thanks to both you guys for your help.

 

[SC woodburner]

Fellas,
Figured I'd update on the stove and seek another bit of advice or opinion. The stove has performed well so far with only one area of concern. Towards the end of a fire, when it's getting down to a coal bed and little wood is left actually burning, sometimes the combustor temp probe jumps/spikes to 1650deg. There is a small crack in the baffle running from the damper to the combustor ring area. I filled this with gasket cement till I can tear it down next spring.

We've followed the op manual directions, getting an established fire with damper open, once combustor temp probe shows 500deg we close damper, once it gets to 800 we reduce primary air and she cooks right up to 1000-1200 for a few hours depending on wood load. We really haven't put more than two splits in and it seems the spike in temp happens even on one split. Manual calls for 2 turns on secondary (combustor) air vent and 2/3 turn on primary (firebox) vent with a medium/low fire setting. We've tried running this a little lower but are still getting a spike occasionally.

Any ideas on the reason this is happening? Any advice on how to avoid the spike or what to do when we see one? Is the crack in the baffle the culprit? If it is I would have thought the spike would have occurred in the first half of the fire. So far we've reduced the primary air and combustor air intakes when we see the temp spike, waited till it cooled a bit and carried on normally. Just concerned about damaging the combustor.
Thanks!

 

[homebrewz]

I don't run a catalyst probe, but I've never seen any obvious signs of a spike in catalyst temp late in the burn cycle. Maybe the coals are not done off-gassing, or there is another crack you're not aware of.. or the existing crack is causing a slight a blow-torch effect. Can't think of anything else.