VC Defiant 1975 Cat C burn issues

[Rusticontheridge]

This is our brand new Defiant.1975 cat C
Picture is stove completely shut down.
Right air control is pushed closed or handle pointing to rear & Cat C on the the left is pushed closed or in the forward position.
CANNOT get this to choke down.
It completely burns out in 3-4 hours.
Top was 653°
Afraid to really stock it, because it goes like an inferno until it burns out.
Checked for air leaks, ash pan door leaked, adjusted that.
Checked all gaskets, nothing.
Used several types of wood with same issues.
Chimney is 20’.
Had a Harman tl200 in same spot with no burn issues.
Looking for suggestions please

 

[VRB Farm]

Hi there fellow Hoosier!

below is where I would start:
1) check cable for air control on rear flapper, two things to look for here, one make sure it is closing correctly (should hear a thunk when closed - our you can look behind the stove at the air intake and confirm. Two check the cable at the air flapper, ensure it is tight and set correctly and make sure the excess tail isn't getting in the way.
2) Good start on the gasket check! These stoves run better with full ash pans, more consistent burn temp (probably sealing some more leads)
- dollar bill check your dampener gasket - mine needed tightening
-flame or incense test all the gaskets - you will be amazed at how many leaks there are
3) if you taking your temp readings on the griddle my experience is those temps will be higher. I have two Stove top gauges on either side of the griddle towards the back corner of the griddle - I run two average the temp between the two halves - probably over kill but prevents me from thinking the stove is at 600 when the other side is still at 350.
4) get Auber digital cat meter probe (shown in back of photo attached) - Photo showing Cat doing its thing at 1400 in the back and stove top at 300 - this was a hot reload, so the coals were there just added some ice cubes to the box. yes I have a cheap blink camera so I can check to see what the stove is doing when I am outside, upstairs in my office, or wondering what I am smelling while laying in bed.
5) these stoves will act completely different during the shoulder season vs when truly cold outside - watch wind speed and direction, I know yesterday was a windy one up here for us.

Start with the above and let us know how you make out. search the forums for both the defiant 2-1 and the encore 2-1, both stoves operate the same. This stove will take three years to learn how to run properly.

You have a beautiful stove, and I really hope you have a cold drafty house - that stove will put out the heat!

My ode to the Encore can be found in the below thread, this is a good starting guide of what I have found to work. (PS - I am no expert - today my Cat was sluggish starting out, then started working great 1100-1200, then the stove started burping... oh happy day! but sure beats burning propane!)
https://www.hearth.com/talk/threads/replacing-30-year-old-encore-new-encore-or-jotul-oslo.202637/#post-2773978

 

[Burnin Since 1989]

It is a great looking stove!

Get an IR thermometer to triple check the magnet thermometers. Some of them can be way off.

My "people" homesteaded in SE Indiana, from Harrison, IN to Milan, IN. I grew up in SW Ohio. My grandparents, both sides owned farms in Milan into the 1970's and 1980's.

 

[begreen]

The burn time with a small load is not surprising. There is only so much fuel in a 1 cu ft load of wood. Definitely check and make sure the air control flapper valve is actually closing. There have been some reports of this not closing completely.

A new catalyst will burn hot until it breaks in. What are the cat temps?

 

[Rusticontheridge]

Hi there fellow Hoosier!

below is where I would start:
1) check cable for air control on rear flapper, two things to look for here, one make sure it is closing correctly (should hear a thunk when closed - our you can look behind the stove at the air intake and confirm. Two check the cable at the air flapper, ensure it is tight and set correctly and make sure the excess tail isn't getting in the way.
2) Good start on the gasket check! These stoves run better with full ash pans, more consistent burn temp (probably sealing some more leads)
- dollar bill check your dampener gasket - mine needed tightening
-flame or incense test all the gaskets - you will be amazed at how many leaks there are
3) if you taking your temp readings on the griddle my experience is those temps will be higher. I have two Stove top gauges on either side of the griddle towards the back corner of the griddle - I run two average the temp between the two halves - probably over kill but prevents me from thinking the stove is at 600 when the other side is still at 350.
4) get Auber digital cat meter probe (shown in back of photo attached) - Photo showing Cat doing its thing at 1400 in the back and stove top at 300 - this was a hot reload, so the coals were there just added some ice cubes to the box. yes I have a cheap blink camera so I can check to see what the stove is doing when I am outside, upstairs in my office, or wondering what I am smelling while laying in bed.
5) these stoves will act completely different during the shoulder season vs when truly cold outside - watch wind speed and direction, I know yesterday was a windy one up here for us.

Start with the above and let us know how you make out. search the forums for both the defiant 2-1 and the encore 2-1, both stoves operate the same. This stove will take three years to learn how to run properly.

You have a beautiful stove, and I really hope you have a cold drafty house - that stove will put out the heat!

My ode to the Encore can be found in the below thread, this is a good starting guide of what I have found to work. (PS - I am no expert - today my Cat was sluggish starting out, then started working great 1100-1200, then the stove started burping... oh happy day! but sure beats burning propane!)
https://www.hearth.com/talk/threads/replacing-30-year-old-encore-new-encore-or-jotul-oslo.202637/#post-2773978

Thanks for the great info.
We’ve tried all of the above, our problem is the stove won’t damper down even with the air intake closed & cat is closed.
It burns like an inferno until all the wood is gone, which is usually 3-4 hours.
Hesitate on loading it up for the night, afraid l will burn the house down.
We had a Quadrafire for 8 years, moved & had a Harman tl200 for 9 & replaced that for this VC.
On our other 2 stoves, we could always damper the fire down.
Did notice on the back of the stove the 2x4 air flow shuts when closed, & won’t draw smoke, but the 2x4 hole above it does. I assume it is the cat airflow?

 

[Rusticontheridge]

Hi there fellow Hoosier!

below is where I would start:
1) check cable for air control on rear flapper, two things to look for here, one make sure it is closing correctly (should hear a thunk when closed - our you can look behind the stove at the air intake and confirm. Two check the cable at the air flapper, ensure it is tight and set correctly and make sure the excess tail isn't getting in the way.
2) Good start on the gasket check! These stoves run better with full ash pans, more consistent burn temp (probably sealing some more leads)
- dollar bill check your dampener gasket - mine needed tightening
-flame or incense test all the gaskets - you will be amazed at how many leaks there are
3) if you taking your temp readings on the griddle my experience is those temps will be higher. I have two Stove top gauges on either side of the griddle towards the back corner of the griddle - I run two average the temp between the two halves - probably over kill but prevents me from thinking the stove is at 600 when the other side is still at 350.
4) get Auber digital cat meter probe (shown in back of photo attached) - Photo showing Cat doing its thing at 1400 in the back and stove top at 300 - this was a hot reload, so the coals were there just added some ice cubes to the box. yes I have a cheap blink camera so I can check to see what the stove is doing when I am outside, upstairs in my office, or wondering what I am smelling while laying in bed.
5) these stoves will act completely different during the shoulder season vs when truly cold outside - watch wind speed and direction, I know yesterday was a windy one up here for us.

Start with the above and let us know how you make out. search the forums for both the defiant 2-1 and the encore 2-1, both stoves operate the same. This stove will take three years to learn how to run properly.

You have a beautiful stove, and I really hope you have a cold drafty house - that stove will put out the heat!

My ode to the Encore can be found in the below thread, this is a good starting guide of what I have found to work. (PS - I am no expert - today my Cat was sluggish starting out, then started working great 1100-1200, then the stove started burping... oh happy day! but sure beats burning propane!)
https://www.hearth.com/talk/threads/replacing-30-year-old-encore-new-encore-or-jotul-oslo.202637/#post-2773978

 

[Smokey Da Bears]

I have the same stove and have also lived through all of the things you mention. What @VRB Farm said in that follow up response are all really good things to check and do. As crazy as it sounds, don't empty that ash pan. It does make a difference. I have never woke up to a warm stove but have dug some coals out of the ashes for a kindling relight. It's been a bit disappointing not to have anything more than a 6 hour burn, but we do enjoy the heat. Watch the VC 2025/2026 performance discussion or read through past years. You'll find nuggets of wisdom.

 

[VRB Farm]

That is your secondary air intake, which feeds the cat chamber but also supplies air into the main fire box, many users have plugged 2-3 of the holes with SS bolts in the fire box to help lower the involuntary air, this has come with success. below thread has the info on this
https://www.hearth.com/talk/threads/encore-2040-cat-c-burns-too-fast.205794/

 

[Rusticontheridge]

That is your secondary air intake, which feeds the cat chamber but also supplies air into the main fire box, many users have plugged 2-3 of the holes with SS bolts in the fire box to help lower the involuntary air, this has come with success. below thread has the info on this
https://www.hearth.com/talk/threads/encore-2040-cat-c-burns-too-fast.205794/

It’s kind of unnerving to let the fire get that hot for combustion chamber, at what point does it get away from you with no way to damper it down?
Sure miss my old Harman Stove.

 

[VRB Farm]

I would read the above thread in the link I sent, it sounds like a 1 for 1 experience of what you are having, some have found new gaskets or the screws did the trick, others was a high draft situation.

It sound to me like you still have air leaking in from somewhere. I would continue filling that ash pan until full, if the stove then calms down you know you found at part of the issue. My ash pan needed significant adjustment.

Keep thinking simple: 3 parts of a fire
Fuel - this isn't where I see your issue, you should be able to still control dry wood but taking away the other two elements
Heat/ignition- (seems we have the box checked here with good heat)
Oxygen - **find the source of this and I think you will get the control you are looking for

I feel like there should be a "you might be a Vermont Casting owners if..." thread that should be started.

If you have worn welding gloves while carrying burning logs out into the yard ... you might be a VC owner.

 

[Turbo89]

That stoves looks very similar to the Encore, I and several others troubleshoot running this stoves in this thread, maybe there’s some tips in there that will help:

https://www.hearth.com/talk/threads/encore-2040-cat-c-burns-too-fast.205794/page-2


I ended up blocking some of the secondary air intake on my encore, and it became much more manageable. This stove also likes a full ask pan, and it likes when you push the coals rearward on the reloads.

I bought mine used so I couldn’t call the installer / VC to put in a warranty claim, but if I were you I’d consider opening a claim while it’s new.

Edit: looks like VRB beat me to it! Haha