VC Defiant II Thermostat issues

[dcm1957]

Hi All.
I bought a brand new VC Defiant II W/S about three years ago. I have a completely vertical flue pipe of 8" diameter that measures about 10 ft in length from the top of the stove to cap above roof, so based on all I've seen the draft should be adequate.
I have a flue pipe temp gauge just above the stove on the oval to round adapter just below the round pipe connection.
I only use SEASONED Oak/hickory firewood that's DRY!...
Since new, When I fire it up, I watch the temp guage until I hit about 500-600 then move the left hand damper lever to the "catalyst mode." (closing the bypass damper technically) I usually keep the temperature lever to max (it's on the right and max is CW or pull handle toward the front of the stove). The stove puts out heat, but the flue temperature gauge will drop down to the 250-350 range and NEVER go into the "catalyst hi temp burn" mode that I see on the other posts. Even if I let it go over 700 then switch over, it still drops to this temperature range.
It's almost as if the thermostat controlling combustion air damper (primary air valve) is choking the stove down. I can LOWER the temperature further by turning this temperature lever CCW (toward the rear).
I've checked the catalyst frequently and it is never "caked up" or "plugged up." It will have slight dust on it.

What's worse is my flue pipe gets a lot of creosote and my exhaust out the stack is far more smokey than the old fashioned (non catalyst) Franklin stove I took out.

The dealer "Heckler Hearth" in Troy MO, basically said. "Gee we don't know how to help it shouldn't do that."

I have the parts blow up diagram that shows this temperature control unit, but it doesn't really show where it is on the stove.

I saw photos of the unit INSIDE the stove on the VC Defiant forum, but WHERE do I gain access to it and where is it located?

Am I on the right track that likely the temp control thermostat is out of adjustment (from the factory I might add)?

What is the procedure to adjust it?

Should I be getting this much smoke and creosote?

Shouldn't I be getting flue temps in the 500-600 range in catalyst mode?

Can anybody help me sort this stove's operation out?

A very frustrated VC Defiant II owner.

 

[defiant3]

So ok, first of all, they haven't made Defiant II's since 1985 or so, so you must have the 2in1, or the model 1975 or 1979. Second, this SO sounds like a draft issue. That stove in particular has a restrictive smoke path and requires a really strong draft or else this is what happens. It's highly unlikely that the draft control assembly is the problem.

Have yoou tried running the stove without the catalyst? Sure would help it breath easier.

 

[webby3650]

Also, everyone thinks they have dry wood. Have you tested it? Has it been split and stacked for more than a year? 10’ from stovetop to cap is very minimal for any stove. Especially a downdraft like yours.

 

[dcm1957]

Mr. Defiant 3... yessir you are correct. It is a model 1975. The manual's filename is Defiant 2 in 1... (which I assumed meant Defiant II) but I see now the manual calls it a Defiant model 1975...
Running the stove bypassing the catalyst makes the temperature soar to over 700+ degrees. I do this to get the fire "HOT" normally.
That will help the creosote situation in the flue pipe, but then WHY did I bother with buying a catalyst W/S to be more "EPA" compliant?
Should I just "remove" the catalyst block and run it through that chamber? Is there any detriment to doing that?

Just for grins to confirm that the air control valve wasn't choking off the combustion air, while still in the catalyst mode, I opened the ash tray door a bit for about 10 minutes. The flames glowed brighter and the front of the stove felt hotter, BUT the flue temp didn't budge at all...

This experiment leads me to believe the combustion air is sufficient, and maybe you're right that the draft isn't sufficient for the downflow. I approximated the height of the flue pipe. The stove is in a 20 x 24 ft room with 9 ft high (at the wall) vaulted ceiling. The stove sits along the low side of the vaulted roofline, not that it matters. The roof pitch is 4/12 and the cap extends about 2 ft above the roof peak... I'll get the EXACT length of this flue and REPOST.

What is the DESIRED length for this flue pipe with this downdraft W/S???

Mr webby360:
My wood is usually 2yr's old and anything over 6"dia is split. I cut and split it myself having lots of wooded acreage to harvest. It's stacked and under rain cover but is outdoors in Missouri (which is fairly humid). I do have about 20% of my wood is small diameter unsplit. How exactly do you "TEST" firewood?

 

[dcm1957]

All, Correction on the EXACT Length. The exposed flue pipe from stove to collar at the ceiling is 5'-6" and the two sections of flue are a 4 foot piece and a 2 foot piece, & the cap is 6" high. SO that makes TWELVE Foot flue not Ten foot I estimated.
As I'm apparently not drawing correctly, I assume this is still too short? How long should it be?
How does the flue pipe diameter effect the draw?
Is 8" the wrong diameter for this stove?

 

[Charles1981]

Also, everyone thinks they have dry wood. Have you tested it? Has it been split and stacked for more than a year? 10’ from stovetop to cap is very minimal for any stove. Especially a downdraft like yours.

The manual for Defiant 1975 2n1 recommends a 16 foot minimum chimney height. I think you hit some major points that need to be strongly considered.

 

[dcm1957]

I guess when all else fails, read the instructions...
I'll see about adding a four foot longer piece to this flue and see how that does...
Thanks ever so much!

 

[defiant3]

Maybe check out the section on operating without the catalytic combustor in there. My understanding is tht it actually functions as tertiary combustion and is optional.