Vermont Castings Defiant not behaving!

[luzugoldens]

I have a Vermont Castings Defiant wood stove with a catalytic converter: serial number 1945. The damper that controls the level of heat located in on the right side of the stove will not shut the fire down even though the flap is closed in the back. The fire burns hot as if the ash pan were open, and it is not. I have to keep the damper completely off to have the fire burn moderately. It is getting much too hot and I can't control the heat as before.
The catalytic converter is fine. The chimney is clean. The gaskets are good. I have been a wood stove owner for many years and this is the first time I have encountered a problem like this. There is no technician in the area who is able to help. Can anyone offer advice? Thanks so much.

 

[begreen]

Welcome. A few guesses would be that the ash pan door is not sealing tightly, the bypass is not closing properly or there is an airleak.

 

[luzugoldens]

Thank you! I have checked the ash pan and it is sealed tightly. Any suggestions on how to check the bypass?

 

[begreen]

I haven't run a VC stove in years, and never the Defiant. Hopefully one of this stove's owners like Defiant will chime in. My guess would be with the fire out or at least very low, to check the bypass linkage with the lid open. Operate it to see if there is too much slop in the linkage or if the bypass plate is not dropping properly into place.

 

[Excavator]

I run into this problem with very dry wood and I just have to close the bypass with stove top temps about 300. I have a cat digital probe that will start showing that the cat hits 500 with in 2 minutes after closing bypass. If I wait till stove top temp hits 500 then I will have hot temps and have trouble controlling. This all has been since I installed insulated liner and new cat. The stove behaves much different now and I had to relearn it. I also will add some greener wood and have better results controlling temps trhen with 2 year old wood
My cat probe has no problem hitting 1200 after 10 minutes and I have to keep eye on it with dry wood. Sometimes it will hit 1700 if I dont turn air down and then it his hard to control.

 

[Diabel]

Sounds like a leaky gasket to me. Dollar bill test or a cigarette lighter test along the seems/doors of the stove will provide some information.
How old is the stove? Did it just start behaving this way overnight?

 

[Charles1981]

I don't quite comprehend the statement about the damper having to be "off" to have a moderately burning fire. By "off" do you mean all the way open or all the way closed.

You have a key damper in the flue/chimney? Or are you talking about the bypass level on the left side of the stove?

 

[begreen]

The Defiant and other VC stoves of that generation have a thermostatically-controlled air intake damper. Off should be meaning closed.

 

[Charles1981]

Well he was talking about the air control level on the right already as a damper and said it is closed. Just wanting to clarify really that the bypass lever on the left is also closed...which it probably is but hasn't really been clear yet.

 

[Diabel]

I am sure he is talking about the air control (primary) lever on the right hand side.
He also mentioned that as he closes the lever all the way the flapper at the back closes all the way. I hope he is not confusing the primary air flapper/door with the secondary air mechanism, that is located above the flapper. Depending on the age and usage of the stove, I would look for air leaks first.

 

[Charles1981]

This is just why I wanted to clarify:
1. bypass damper (updraft/cataltyic) control lever on the left.
2. air (thermostat) control lever on the right.
3. air (thermostat) control "flap" (damper you could kind of call it) is on the underside of the stove to the back

There isn't any other way to control the fire than plugging primary air intakes in the stove which isn't recommended.

Just wanted to make sure there are the 3 conditions that are being met. 1. The bypass is closed and in catalytic mode. 2. He has the thermostat lever closed all the way. 3. the thermostat flap/damper closely completely underneath and in back of the stove when the thermostat lever is completely closed.

If all of these conditions are met. And the stove was working properly before and now it is not would definitely mean there is an air leak whether it is an air leak, bad gasket, crack in the stove.

But to me it was not 100% clear and I just wanted to make sure those conditions were met and that he doesn't have any additional dampers in the flue/chimney ect.

 

[Charles1981]

It would appear I have some terminology mixed. The thermostat is considered primary air control, and the secondary air are the air intakes that should not be plugged based on stove diagrams and parts list.

 

[Diabel]

Good input/questions Charles

We'll see if he comes back with answers.

 

[Diabel]

It would appear I have some terminology mixed. The thermostat is considered primary air control, and the secondary air are the air intakes that should not be plugged based on stove diagrams and parts list.

I never read the manual.
The way I see it:
The lever on the right hand side (facing the stove) controls the primary air... The flapper at the back bottom of the stove (little door).

Up above thatlittle door, is the secondary air control attached to the bio-metallic spring. That flapper only moves 1/4 inch up or down depending on the temperature measured in the refractory box below the cat by a probe that is attached to the same bio-metallic mechanism.

The holes you mention one on each side of the stove by the ash pan (in my opinion) are only there to prevent chocking the fire completely (industry requirements). There is no control over these holes, other than plugging them.

 

[Woody Stover]

I wonder how long it's been since the gaskets were replaced? They may look fine, even pass the $1 test, but I think they can still be better with new ones. And what about the glass gaskets? I replaced all gaskets on the Buck...door, door glass, bay windows and ash pan, with OEM. Now I have great control of the burn.