What is the expected behavior of a worn out catalytic combustor?

[oldAGE]

After reading a few recent posts and experiencing some problems on my 2000 VC Encore 2550, I have this question - What would the expected behavior be of my stove if the catalytic combustor is worn out.

It is a Vermont Castings 2550 Encore - model year 2000. I am the original owner and installed it new. She has 8" double walled DuraVent stove pipe for about six feet to over 16' of stainless double walled chimney through 8' of insulated wall and boxed in above the roof line.

I burn her as aux heat during the heating season from Oct - March maybe a couple of times a week and most every weekend. She is very well cared for and I (until recently) keep it controlled consistently below 650 degrees.

I have cleaned and checked the refractory and cleaned out the combustor. It is solid (just one or two honeycombs seem to be a slight bit damaged) and was clear. I am currently awaiting a new secondary air probe assembly as the old one is beginning to wear and it's an easy replacement. I have recently regasketed just about everything that is reachable.

So, what should I expect if the cat just doesn't have it any more? Faster fuel consumption? Hotter fires? Stronger draft (like the damper isn't engaged at all)?

Thanks for everyone's assistance to this point.

AGE

 

[hounddog]

;

 

[Backwoods Savage]

According to our manual:

1. Your stove will generate noticeably less heat.

2. You will notice a dramatic increase in the amount of soot and/or creosote in the stovepipe or chimney.

3. The color of the smoke produced by the stove will change. Smoke will appear black or brownish instead of clear white smoke (almost steam) from a catalytic stove.

 

[eernest4]

Hi old age,

Very good question & well thought out post. Wish I knew the answer to it , but my stoves are all secondary burn models, so i dont have a clue.

I'm getting to old age ,too & I am realizing more & more that it ain't easy getting old, not one bit! In fact, the older you get,the
more it hurts & in more places ,too

See if your owners manuel has a trouble shooting section & look under catalic converters or combusters.

If you don't have /cant find your owners manuel,you can download it for free from the manufactures website into your computer's hard drive & print it out, if you choose.

 

[swestall]

Many of the VC stoves are set up so you can see the CAT glowing when engaged if you don't have a full load in front of the CAT chamber entry.
So, you can look in there when it is dark, if there is no glow, the CAT is not working properly.
As was said in the other post, you have to change that thing out every few years or so. BUT, don't let this discourage you as you have the BEST stove VC has to offer. You get great secondary burns with the VC CAT stove and your stack remains clean as well as producing good heat. Not to mention that your stove does not take a lot of your time to operate. In the long run spending a couple hundred every few years for a CAT is really not that much money for a great functioning stove. Just do it and be happy.
Of course, make sure it is not glowing first. If you get the stove top up to about 600 and the pipe 600+ and engage it there is no reason it should not lite off like a roman candle. If no glow under those conditions, get a new one.

 

[elmoleaf]

Change in smoke color as mentioned is the easiest clue.
However, I'd guess at 7-8 years old, your combuster is overdue for replacement.

 

[oldAGE]

OK, in response to what I have heard thus far...

1) I am not getting less heat. I am actually getting more heat (part of the problem) - I am getting an overfire condition and wondering how a bad CC would affect how my stove works.
2) I am getting more smoke out of my chimney when damper engaged yet it is white smoke, not black. Just seems to be more smoke than usual.
3) I am not concerned about the creosote issue yet. Just trying to figure out what is going on with my baby.

Concensus is that no matter how you slice it, it is time for a new CC anyway.

So, by the end of this week my stove will have all new gaskets (where the average homeowner can regasket) a new secondary air probe, and a new CC on the way. At that point, I will be at a total loss and we will see what VC customer service can tell me since my dealer thinks there is nothing wrong me burning down my home. :ahhh:

AGE

 

[begreen]

Has the stove ever been regasketed? This could be a combination of issues, old combustor and air leaks. It sounds like you are on the right course with new gaskets and secondary probe. Give it a real thorough vacuuming too. If you have a compressed air nozzle, put on a mask and blow out every crevice. That will sometimes expose seam leaks.

 

[oldAGE]

When you say "regasketed," are you referring to the actual sides, back, bottom and top -- as in a complete rebuild or are you talking about the usual -- doors, ash pan, windows, and interior panels like the box sides and fireback? If the latter, then yes, everything is either brand new or reseated. If you are talking about the former, then no... and that's a horse of a different color.

AGE

 

[begreen]

Yes, that's what I meant, but while doing a regasketing and cleanout, the other seams may need caulking with stove cement if you discover leaks in them. If leaks are ignored, the stove may not improve as much as hoped for.

 

[oldAGE]

"Yes" Back, Sides, Bottom and Top? or "Yes" Doors, Ash Pan, Griddle, etc?
AGE

 

[begreen]

Inspect every non-gasketed seam. This is where the sides/front or back join, and the top and bottom seams. They could be fine, but it's worth a good inspection at this stage. If leaking, seal them up.

 

[oldAGE]

I have already done a light, flame, and smoke test with a fire running. The light test looking for light coming through the seams. The flame test running a flame around the obvious seams looking for the flame to be "sucked" in, and a smoke test for the same. Nothing conclusive. Looks like I will take everything apart again down to the skeleton inside and look again but that's the killer part. Everything that I can see and test seems to be coming back fine.

AGE

 

[swestall]

Did you double check the large gasket that seals the main damper plate?

 

[oldAGE]

I checked on your advice last week... it's still there and still whole but I am going to yank it this week. Needed to get a 5/16th gasket and my local stores were out until yesterday. Haven't gotten to it yet. It stinks that it is inside the upper fireback so it's inverted and not easily accessible. I assume the best way to get to it will be from the top through the stove pipe. The kicker is that my stove pipe is a tight fit so I have to take down a riser, a 45, two feet, another 45, and the chimney mount. Being that it's below zero and I didn't want to mess with an 8" hole through my house, I didn't want to mess with it just yet. It's too bad. The gasket work will be about 5 minutes and the stove pipe work will take me an hour.

AGE

 

[crazy_dan]

According to the Buck stove website their cat has a 6 year life expectancy.
anyway here is a link to their page hope this helps
(broken link removed to http://www.buckstove.com/faq.html#WHY_DO_COMBUSTORS_NEED_REPLACED)

 

[downeast]

< (broken link removed to http://www.sud-chemie.com) > or 1.800.637.1644, Matt Daniels is the in-country wood stove catalyst engineer in Massachusetts. They're very helpful on the tel.
The web site is huge since Sud Chemie is an international conglomerate.
Good luck. Plenty of information to sift through here AGE.

 

[Heat Miser]

A good indicator of a spent cat element is blue/black smoke coming from the chimney once the stove is at proper operating temperature. My cat element will glow only when there is a lot of smoke. When the fire is burning well it won't glow at all but it is working as there is no smoke coming from the chimney. A good working cat will have just heat vapor and occasionally some white steam which quickly dissipates from the chimney. Of course, there should be no creosote formation in the chimney either.