Brand new Vermont Castings Defiant 1975-CAT-C

[RatherCutWoodThanGoToWork]

I had a VC Defiant Professionally installed brand new Fall 2021. Brick chimney 35' with new 6" liner. Previously used with Drolet non cat, one year, and VC Defiant from 1980, rebuilt, used one year, still leaked so abandoned for new. Waited 6 months for unit to be built. Super excited to buy a REAL stove.(Real expensive)
The new stove is beautiful (Twilight, but not blue enough for me) and easy and efficient compared to older models. Efficient as if Half the wood of old leaky stoves and SUPER easy ash removal over the DROLET. Oh, no its NOT too big. I have an old cold basement made of cement and brick, and I am happy and warm for the first winter in my life. Except that everyone wants to sit in the basement rather than leaving me alone in my happy place.

Problem: Cat disintigrated after a month in the fall. I read the instructions. I followed firing proceedure. I can regale you with the limitations of the stove, feel free to ask, or accuse me of ignorance, or stove abuse. I want to know what I did wrong. The dealer can't tell me. Stove was never over-fired. Temp was consistent and within spec. Wood was flawless oak. Perfectly seasoned. Not even wet from snow or rain. It was easy to operate and maintain.
Second CAT supplied under warranty. I monitored even closer checking for temperature fluctuations or spikes for a week. Cleaned, all OK, Looked whitish but clean as a whistle. A month goes by and the cleaning shows a cat disintegrated in the housing. Dealer and manufacturer are confused. The only unexplained is the steel sheet in between the firebrick in back of the stove is misaligned compared to exploded diagram in instructions, but CAT fit fine and temp gauge moved when stove was at temp-(I was told the probe gauge did nothing, I figured it out). It doesn't seam to leak, but dampening down required engaging cat, thusly sending heat over cat. Maybe the internal auto temp damper is not restrictive enough. Most people have draft problems. I do not.

Am I the only Human to buy one of these new ones? or am I the only one to actually use it instead of just look at it? I can't find anyone on the entire Internet who has posted operation of this unit new. Either I am the only one with a defective unit, or the only one with a new one that uses it. Am I the only one with Two CATs that disintigrated in a month? They are supposed to work at 1000F, My stove has never been that hot. And it doesn't burn cold.

I fix things for a living more complex than a cast iron box. Anyone have experience with disintigrating Catalytic combusters?

It has been working fine without CAT, just more smokey. I would like it to work as I paid a large sum for the very reason of efficiency.

 

[bholler]

Your problems with all of the stoves were most likely caused by excessive draft due to your 30' chimney. Install a pipe damper or two and things will work much better

 

[RatherCutWoodThanGoToWork]

Thank you for the advice. I asked dealer/installer the same thing, he didn't do it. I only paid for install for insurance companies sake. I will be installing secondary flue damper to slow draw. It does pull like a train. I have had the opposite in other installs, exterior or short stack. As I am mr. fix it till deaths door(I will tighten the knob to hell, or oil St. Peters Gate) Most folks have a draft problem, I do not. I forgot to mention the previous stoves I Did have a flue damper. And had to reinstall and re-fab and cement properly the damper flap to function properly. Including this house on other non cat stoves. That helped. You are the first person to give me actual problem solving advice. 1920 house. Fighting the good fight in This Old House, Que the bass Clarinet, Bob Villa.

 

[bholler]

At 30' one damper may not be enough. The only way to know is a draft measurement. There should never be any cement on a damper anywhere .

 

[Loueze]

See…. This forum is the best.
I have the exact same stove in that color and a 25’ chimney (triple wall stainless 8”, no turns , run inside the house until it goes through the roof .
Then 10 feet more straight up)
I have had the stove one season and love how much capacity it has , but when I put too much wood in it , I can’t control the heat.
It never shows mid range on the catalytic, always in the low side ,
My wood is mostly ash , 2 years old and some oak. The ash trees here (north east New Jersey) are all dying , so that’s the predominant delivered splits .
Mine are huge though because the VC firebox is so big. The regular splits burned up in no time last year .

I have a broken part near the corner of the cat and can see that when it gets hot again , it’s going to need replaced . Lots of chips and cracks .Maybe that’s why the temperature is low ….
In order to try and get some control, I added a round cast iron damper about 20 inches from the top of the stove .
It didn’t make a difference at all.
I have control of the stove , just not enough if the fire is rolling … if I shut the air down all the way and closed the damper , it’s more controlled , but smokes the glass so bad it’s pointless .
being “glass”
But , I have never considered a second damper
Only here would that even be a thought !
So , obviously, it’s time for a new cat and a second damper attempt.
I wonder if the “metal” cats offered are worth a try
Somebody said they heat up quickly . Maybe that’s better .

Anyway , except for the fact that there is very little point in putting glass on the front because it’s always black , I love the stove and its looks and hope that someday I’ll learn how to run it properly.
Just wanted you to know your not alone .

 

[Loueze]

At 30' one damper may not be enough. The only way to know is a draft measurement. There should never be any cement on a damper anywhere .

i don't understand why you said "there should never be any cement on a damper

 

[bholler]

i don't understand why you said "there should never be any cement on a damper

Because the poster said they cemented their flue damper. There is no place on a flue damper where cement should be used

 

[Loueze]

I went back and saw exactly what you are talking about . Thanks
Do you have an opinion about the metal cats vs. the ceramic (stock) . I need yo buy one and don't know anything about the the difference

 

[bholler]

I went back and saw exactly what you are talking about . Thanks
Do you have an opinion about the metal cats vs. the ceramic (stock) . I need yo buy one and don't know anything about the the difference

Metal cats handle thermal shock better than ceramic but clog easier

 

[Woodsplitter67]

I agree with @bholler, Im a big fan of the steel cat. I started running it years ago and found that they light off quicker and normally dont run super hot in my stove

 

[AsylumResident]

I have the VC Defiant-Cat-C that I purchased spring of 2023. I found the provided thermoprobe on the cat didn't really give me a good idea of where the temp was actually at, I replaced it with a digital one. My chimney is about 18' tall, also installed in the basement, with a 90 degree elbow and a T. My draft is not to low, I have measured it periodically and at times my draft is too much and things start to over fire. I would agree that your 35' chimney would have a very strong draft! When my draft gets to high with the CAT engaged, I have seen temps over 1,800 at the CAT. My ceramic CAT lasted three months. I a bought a metal cat and have been using that the end of last year and into this year. Nothing bad yet but it hasn't been that long. It does light off faster.

 

[Loueze]

Metal cat and second damper coming up.
I have the first dampner 20" up from the stove. Any suggestions where the second one should go?

The first one is the classic cast iron plate with the rod going through it. You drill 2 holes and then try to figure out how to put that rod through the cast iron flapper and get the spring and retainer all lined up together .
Possible , but tricky.

The new one is a Dura Vent 8" that's already assembled.. Looks like it should be a better fit. It should be . its 10 times the price .
My question is where do i put it?
Thanks

 

[Woodsplitter67]

Metal cat and second damper coming up.
I have the first dampner 20" up from the stove. Any suggestions where the second one should go?

The first one is the classic cast iron plate with the rod going through it. You drill 2 holes and then try to figure out how to put that rod through the cast iron flapper and get the spring and retainer all lined up together .
Possible , but tricky.

The new one is a Dura Vent 8" that's already assembled.. Looks like it should be a better fit. It should be . its 10 times the price .
My question is where do i put it?
Thanks

Just a heads-up.. My first year I totally struggled with running the cat. That bimetal temp probe is terrible. You really cant run the stove to its full potential and or actually see what the stove is doing. You just get active zone and bimetal probes are notoriously inaccurate.

Get the auber AT100 and see in real time what the stove is doing

Below is a picture of my stove running last December.. the fire in it. the cat temperature at 1201 and the stove top temperature with an IR gun. No guess work I know for a fact that this stove is running well

 

[aheeejd]

I had a Defiant 1975 Cat C professionally installed a couple years ago. I hate the thing. Just had my 3rd or 4th chimney fire. I cleaned it (the pipe) 2 months ago, & just checked horizontal pipe a month ago for ash build up. Was totally clean. This morning I wake up, open dampers (stove only, none in pipe) & tossed in 2 3" diameter, 7" long round pieces. Next thing my fire alarms were going off. Horizontal pipe was red. I shut both dampers. Go look outside, few sparks coming out. Soot flakes all over area. It's all calmed down now.

I do have a very tall chimney, probably 30' +. Not really positive. I often wondered why install had no damper in pipe. Reading here I see that I should have one. Maybe 2. Not much room for 2. Goes out wall, then up. I have no idea if my cat is toast. I need to get a pro here. But can anyone give me anything to help. Like can I tell (what to look for) if my cat is junk. Thank you.